Fix FCM not initialized crash.

app/src/main/java/org/thoughtcrime/securesms/gcm/FcmUtil.java

@@ -1,10 +1,12 @@
 package org.thoughtcrime.securesms.gcm;
 
+import android.content.Context;
 import android.text.TextUtils;
 
 import androidx.annotation.WorkerThread;
 
 import com.google.android.gms.tasks.Tasks;
+import com.google.firebase.FirebaseApp;
 import com.google.firebase.messaging.FirebaseMessaging;
 
 import org.signal.core.util.logging.Log;
@@ -20,8 +22,12 @@ public final class FcmUtil {
    * Retrieves the current FCM token. If one isn't available, it'll be generated.
    */
   @WorkerThread
-  public static Optional<String> getToken() {
+  public static Optional<String> getToken(Context context) {
     String token = null;
+
+    // Must be called manually if running outside of main process
+    FirebaseApp.initializeApp(context);
+
     try {
       token = Tasks.await(FirebaseMessaging.getInstance().getToken());
     } catch (InterruptedException e) {