Allow for alternative Default Welcome message on G4 Doorbell
<!-- FEATURE REQUESTS THAT ARE NOT FILLED OUT COMPLETELY WILL BE CLOSED AUTOMATICALLY WITHOUT WARNING AND WILL NOT RECEIVE A RESPONSE. THE FORM IS HERE FOR A REASON. :). -->
<!-- Please ensure you read the documentation before creating a feature request to ensure the functionality doesn't already exist. -->

**Is your feature request related to a problem? Please describe:**
No
<!-- A clear and concise description of what the problem is or what use case you would like to see supported. e.g. I'm always frustrated when [...] -->
**Problem**
We use the doorbell in a bilingual part of Wales, So I've changed the default greeting from WELCOME to CROESO/WELCOME to display always on the screen. When switching to another message (eg "Leave Package at Door") for 30 seconds, the doorbell reverts to the Welcome message rather than the preferred default that was set.

**Describe the solution you'd like:**
Allow the option to set a default message to revert on the message screen back to after the timeout period has completed on selection
<!-- A clear and concise description of what you want to happen. -->

**Describe alternatives you've considered:**
Unable to set a new default message in the protect app other than just reset the custom message and set to always once again.
<!-- A clear and concise description of any alternative solutions or features you've considered. -->

**Additional context:**
<!-- Add any other context or screenshots about the feature request here. -->

<!-- Click the "Preview" tab before you submit to ensure the formatting is correct. -->
