Doorbell "leave package at door" trigger via MQTT
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**Is your feature request related to a problem? Please describe:**
For the Unifiy Doorbell: I'd like to trigger the built in "leave package at door" with icon via MQTT. 

**Describe the solution you'd like:**
I'd like to be able to trigger the built in "leave package at door" message with icon via MQTT.

**Describe alternatives you've considered:**
Using the custom message via MQTT, which works, but I'd like to trigger the built in message so I get the package icon.

**Additional context:**
No more additional context.

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