refactor(messaging, android): removed unsafe & deprecated API. E.g. LocalBroadcastManager replaced by LiveData

[russellwheatley]

Description

This effects the refreshToken & onMessage API. For completeness, I also tested the onMessageOpenedApp & the onBackgroundMessage handler. They all worked as intended.

List of changes made:

• Removed LocalBroadcastManager API in favour of the recommended LiveData API.
• Updated AGP to v8.
• Removed Jetifier as it is not needed anymore.
• deprecated sendMessage() as the underlying android API send() is deprecated and will be decommissioned in June 2024.
• Update some API according to android studio linting for unchecked API.

Related Issues

Addressed some messaging warnings for this issue: #8073

Still need to return and work on the JobIntentService which has a number of deprecated API.

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Breaking Change

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