[Bug] Humidity sensor on thermostat exposed as separate service
### Is there an existing issue for this?

- [X] I have searched the existing issues

### Describe the bug

When a thermostat also exposes a humidity sensor on the same endpoint, the humidity sensor currently gets configured as a secondary service, and not as the optional `CurrentRelativeHumidity` characteristic for said thermostat service.

It's (for some reason?) not possible to ungroup these two services, meaning the accessory tile in Home will only show a sensor icon and not the current state of the thermostat.


A possible solution might be to simply skip service creation for humidity sensors in case `climate` is also exposed on the same endpoint. Adding the optional characteristic should also be rather trivial, because we probably can reuse proven code from #854. 😉

### Related devices

_No response_

### Related Devices

- RBSH-RTH0-ZB-EU
- RBSH-RTH0-BAT-ZB-EU

### Steps To Reproduce

_No response_

### Expected behavior

A thermostat service with the optional `CurrentRelativeHumidity` characteristic gets exposed to HomeKit, and no additional humidity service is created.

### Device entry

```json
[…]
"exposes": [
        {
          "features": [
            {
              "access": 5,
              "description": "Current temperature measured on the device",
              "label": "Local temperature",
              "name": "local_temperature",
              "property": "local_temperature",
              "type": "numeric",
              "unit": "°C"
            },
            {
              "access": 7,
              "description": "Temperature setpoint",
              "label": "Occupied heating setpoint",
              "name": "occupied_heating_setpoint",
              "property": "occupied_heating_setpoint",
              "type": "numeric",
              "unit": "°C",
              "value_max": 30,
              "value_min": 4.5,
              "value_step": 0.5
            },
            {
              "access": 7,
              "description": "Temperature setpoint",
              "label": "Occupied cooling setpoint",
              "name": "occupied_cooling_setpoint",
              "property": "occupied_cooling_setpoint",
              "type": "numeric",
              "unit": "°C",
              "value_max": 30,
              "value_min": 4.5,
              "value_step": 0.5
            },
            {
              "access": 7,
              "description": "Offset to add/subtract to the local temperature",
              "label": "Local temperature calibration",
              "name": "local_temperature_calibration",
              "property": "local_temperature_calibration",
              "type": "numeric",
              "unit": "°C",
              "value_max": 5,
              "value_min": -5,
              "value_step": 0.1
            },
            {
              "access": 7,
              "description": "Mode of this device",
              "label": "System mode",
              "name": "system_mode",
              "property": "system_mode",
              "type": "enum",
              "values": [
                "off",
                "heat",
                "cool"
              ]
            },
            {
              "access": 5,
              "description": "The current running state",
              "label": "Running state",
              "name": "running_state",
              "property": "running_state",
              "type": "enum",
              "values": [
                "idle",
                "heat",
                "cool"
              ]
            }
          ],
          "type": "climate"
        },
        {
          "access": 5,
          "description": "Measured relative humidity",
          "label": "Humidity",
          "name": "humidity",
          "property": "humidity",
          "type": "numeric",
          "unit": "%"
        },
        {
          "access": 7,
          "description": "Bosch-specific operating mode (overrides system mode)",
          "label": "Operating mode",
          "name": "operating_mode",
          "property": "operating_mode",
          "type": "enum",
          "values": [
            "schedule",
            "manual",
            "pause"
          ]
        },
        {
          "access": 7,
          "description": "Enable/disable window open (Lo.) mode",
          "label": "Window detection",
          "name": "window_detection",
          "property": "window_detection",
          "type": "binary",
          "value_off": "OFF",
          "value_on": "ON"
        },
        {
          "access": 7,
          "description": "Activate boost heating (5 min. on TRV)",
          "label": "Boost heating",
          "name": "boost_heating",
          "property": "boost_heating",
          "type": "binary",
          "value_off": "OFF",
          "value_on": "ON"
        },
        {
          "access": 7,
          "description": "Enables/disables physical input on the device",
          "label": "Child lock",
          "name": "child_lock",
          "property": "child_lock",
          "type": "binary",
          "value_off": "UNLOCK",
          "value_on": "LOCK"
        },
        {
          "access": 7,
          "description": "Sets the display on-time",
          "label": "Display ontime",
          "name": "display_ontime",
          "property": "display_ontime",
          "type": "numeric",
          "unit": "s",
          "value_max": 30,
          "value_min": 5
        },
        {
          "access": 7,
          "description": "Sets brightness of the display",
          "label": "Display brightness",
          "name": "display_brightness",
          "property": "display_brightness",
          "type": "numeric",
          "value_max": 10,
          "value_min": 0
        },
        {
          "access": 1,
          "category": "diagnostic",
          "description": "Link quality (signal strength)",
          "label": "Linkquality",
          "name": "linkquality",
          "property": "linkquality",
          "type": "numeric",
          "unit": "lqi",
          "value_max": 255,
          "value_min": 0
        }
      ]
[…]
```


### Status update

_No response_

### Messages from this plugin

_No response_

### This plugin

1.11.0-beta.5

### Homebridge

1.7.0

### Zigbee2MQTT

1.37.1-dev

### Homebridge Config UI X (if applicable)

_No response_