android: update to 23.4.1

[m1ga]

Changelog:

23.4.0

• The SDK now calls messageHandled() after a message has been handled successfully.
  (note: couldn't find anything in the help about that)
• Added an internal identifier to meet compliance requirements.

23.3.1

• Added metadata to FirebaseInstanceIdReceiver to signal that it finishes background broadcasts after the message has been handled.
• Specified a notification's dismiss intent target via an action instead of component name.

firebase.cloudmessaging-android-3.4.3.zip

[m1ga]

Quick note here:
this is the last version in the 23.4.x branch! 24.0.0 has compile SDK 34+, min SDK 21+ (should both be fine).
But we'll need to update all other modules with it. Currently having a hard crash when using 24.0.2 with many other old firebase modules.