stop using deprecated firebase iid (#751)

In order to solve #741 it seems we need to stop using firebase iid that is [deprecated](https://firebase.google.com/docs/reference/android/com/google/firebase/iid/package-summary). As part of it, I bumped the firebase-messaging version to 21.1.0

Co-authored-by: Yogev Ben David <[email protected]>

Author: DanielEliraz

lib/android/app/build.gradle

@@ -12,7 +12,7 @@ def DEFAULT_COMPILE_SDK_VERSION = 29
 def DEFAULT_MIN_SDK_VERSION = 21
 def DEFAULT_KOTLIN_VERSION = "1.3.61"
 def DEFAULT_KOTLIN_STDLIB_VERSION = "kotlin-stdlib-jdk8"
-def DEFAULT_FIREBASE_MESSAGING_VERSION = "20.2.0"
+def DEFAULT_FIREBASE_MESSAGING_VERSION = "21.1.0"
 
 def androidSdkVersion = safeExtGet('androidSdkVersion', DEFAULT_COMPILE_SDK_VERSION)
 def androidMinSdkVersion = safeExtGet('androidMinSdkVersion', DEFAULT_MIN_SDK_VERSION)

lib/android/app/src/main/java/com/wix/reactnativenotifications/fcm/FcmToken.java

@@ -7,10 +7,7 @@
 import com.facebook.react.ReactApplication;
 import com.facebook.react.ReactInstanceManager;
 import com.facebook.react.bridge.ReactContext;
-import com.facebook.react.modules.core.DeviceEventManagerModule;
-import com.google.android.gms.tasks.OnSuccessListener;
-import com.google.firebase.iid.FirebaseInstanceId;
-import com.google.firebase.iid.InstanceIdResult;
+import com.google.firebase.messaging.FirebaseMessaging;
 import com.wix.reactnativenotifications.BuildConfig;
 import com.wix.reactnativenotifications.core.JsIOHelper;
 
@@ -75,17 +72,19 @@ public void onAppReady() {
     }
 
     protected void refreshToken() {
-        FirebaseInstanceId.getInstance().getInstanceId().addOnSuccessListener(new OnSuccessListener<InstanceIdResult>() {
-            @Override
-            public void onSuccess(InstanceIdResult instanceIdResult) {
-                sToken = instanceIdResult.getToken();
+        FirebaseMessaging.getInstance().getToken()
+            .addOnCompleteListener(task -> {
+                if (!task.isSuccessful()) {
+                    if (BuildConfig.DEBUG) Log.w(LOGTAG, "Fetching FCM registration token failed", task.getException());
+                    return;
+                }
+                sToken = task.getResult();
                 if (mAppContext instanceof IFcmTokenListenerApplication) {
                     ((IFcmTokenListenerApplication) mAppContext).onNewFCMToken(sToken);
                 }
                 if (BuildConfig.DEBUG) Log.i(LOGTAG, "FCM has a new token" + "=" + sToken);
                 sendTokenToJS();
-            }
-        });
+            });
     }
 
     protected void sendTokenToJS() {