Support android FCM notification delegation proxy controls

[mikehardy]

What feature would you like to see?

Looks like there is a new potential meta-data addition and 3 methods available in the firebase-android-sdk to support a new "notification proxy delegation" feature

Use of the notification proxy delegate is related to FCM message priority, delivery rates, and delivery rate reporting so affects a number of use cases critical to apps using the react-native-firebase / notifee combo that need fine-grained control over and ability to report on message delivery

These features were introduced in two phases, with the last one (so a sufficient release to assume we have APIs in place is) being Firebase Android BoM (Bill of Materials) version 29.0.0 - so everyone should have this by now

Info

https://firebase.google.com/docs/cloud-messaging/android/message-priority#proxy

APIs

https://firebase.google.com/docs/reference/android/com/google/firebase/messaging/FirebaseMessaging#isNotificationDelegationEnabled()
https://firebase.google.com/docs/reference/android/com/google/firebase/messaging/FirebaseMessaging#setNotificationDelegationEnabled(boolean)
https://firebase.google.com/docs/reference/android/com/google/firebase/messaging/FirebaseMessaging#setDeliveryMetricsExportToBigQuery(boolean)

AndroidManifest.xml meta-data key, noted in same API docs:
https://firebase.google.com/docs/reference/android/com/google/firebase/messaging/FirebaseMessaging#setNotificationDelegationEnabled(boolean)