Add Code to HomeAssistant MQTT Discovery
## Alarm system
EVO192 version 6.86
IP(IP150) Module version 20, firmware: 1.34

## Environment

Home Assistant Integration:

Version | 2020.12.2
-- | --
Installation Type | Home Assistant OS
Development | false
Supervisor | true
Docker | true
Virtual Environment | false
Python Version | 3.8.6
Operating System Family | Linux
Operating System Version | 5.4.84
CPU Architecture | x86_64



## Git branch
Current version: 2.2.4

## Describe the bug
Adding a code to the home assistant interface is not honored and the alarm may be set without a valid code. See documentation

https://github.com/ParadoxAlarmInterface/pai/wiki/Home-Assistant-integration#homeassistant-keypad

## To Reproduce
Steps to reproduce the behavior:
1. Configure the home assistant integration via IP and MQTT access.
2. Add an alarm_panel entity to the UI using one of the partitions on the Paradox system:

![image](https://user-images.githubusercontent.com/6507120/103787332-1f6b7180-5046-11eb-85c4-ec2632c522cc.png)   
   
Lovelace yaml:   
```yaml
type: alarm-panel
states:
  - arm_home
  - arm_away
entity: alarm_control_panel.inside
```

3. You will notice there is no keypad, now follow the [documentation](https://github.com/ParadoxAlarmInterface/pai/wiki/Home-Assistant-integration#homeassistant-keypad) to enable the keypad.
   
![image](https://user-images.githubusercontent.com/6507120/103787842-cfd97580-5046-11eb-9295-78cce14e73d0.png)


Observe that the customize.yaml was updated by home assistant:

![image](https://user-images.githubusercontent.com/6507120/103788039-10d18a00-5047-11eb-908c-3acc8867c623.png)
   
4. Restart the home assistant instance  or reload the customisations under server controls.
5. You will notice the lovelace entity still doesn't require a code.
 
![image](https://user-images.githubusercontent.com/6507120/103788787-eaf8b500-5047-11eb-9675-72d8c8ce21c6.png)

I would expect the UI to now show the Keypad.
I have confirmed that my customize.yaml is included in my main configuration file of home assistant.
```yaml
homeassistant:
  customize: !include customize.yaml
```
