Add foreground service type to MagicFirebaseMessagingService

Since SDK 31 foreground services can't start while running in
background, except for a few special cases like phone calls.

See:
 - https://developer.android.com/guide/components/foreground-services#background-start-restrictions

Signed-off-by: Tim Krüger <t@timkrueger.me>

app/src/gplay/AndroidManifest.xml

@@ -39,7 +39,8 @@
 
         <service
             android:name=".services.firebase.MagicFirebaseMessagingService"
-            android:exported="false">
+            android:exported="false"
+            android:foregroundServiceType="phoneCall">
             <intent-filter>
                 <action android:name="com.google.firebase.MESSAGING_EVENT"/>
             </intent-filter>