[Android] Verified if the FirebaseApp is not already running before initialization.

[darshanio]

Description of Change

• Addressed an issue where if the FirebaseApp is initialized before the RequestNativeToken in Android is invoked, the FirebaseApp fails to load.

Issues Resolved

• This resolves an issue where Google Crashlytics needs FirebaseApp instance in Maui App's onCreate handler either by using ConfigureLifecycleEvents in MauiProgram or by implementing Shiny.Hosting.IAndroidLifecycle.IOnActivityOnCreate.
• Avoids FirebaseApp name [DEFAULT] already exists! error with following StackTrace:

 at Java.Interop.JniEnvironment.StaticMethods.CallStaticObjectMethod(JniObjectReference type, JniMethodInfo method, JniArgumentValue* args) in /Users/runner/work/1/s/xamarin-android/external/Java.Interop/src/Java.Interop/obj/Release/net7.0/JniEnvironment.g.cs:line 21452
    at Java.Interop.JniPeerMembers.JniStaticMethods.InvokeObjectMethod(String encodedMember, JniArgumentValue* parameters) in /Users/runner/work/1/s/xamarin-android/external/Java.Interop/src/Java.Interop/Java.Interop/JniPeerMembers.JniStaticMethods.cs:line 165
    at Firebase.FirebaseApp.InitializeApp(Context context, FirebaseOptions options) in C:\a\_work\1\s\generated\com.google.firebase.firebase-common\obj\Release\net7.0-android\generated\src\Firebase.FirebaseApp.cs:line 627
    at Shiny.Push.PushManager.DoInit()
    at Shiny.Push.PushManager.RequestNativeToken()
    at Shiny.Push.PushManager.RequestAccess(CancellationToken cancelToken)

API Changes

None

Platforms Affected

• Android

Behavioral Changes

None

Testing Procedure

None

PR Checklist

• [x] Rebased on top of the target branch at time of PR
• [x] Changes adhere to coding standard
• [x] Sent to a v(branch) or DEV branch

[aritchie]

Thanks for the PR