Remove conflicting deps.

Author: jonsimantov

Android/firebase_dependencies.gradle

@@ -25,8 +25,7 @@ def firebaseDependenciesMap = [
   'auth' : ['com.google.firebase:firebase-auth'],
   'database' : ['com.google.firebase:firebase-database'],
   'dynamic_links' : ['com.google.firebase:firebase-dynamic-links'],
-  'firestore' : ['com.google.firebase:firebase-firestore',
-                 'com.google.guava:guava:32.1.3-android'],
+  'firestore' : ['com.google.firebase:firebase-firestore'],
   'functions' : ['com.google.firebase:firebase-functions'],
   'gma' : ['com.google.android.gms:play-services-ads:23.0.0',
            'com.google.android.ump:user-messaging-platform:2.2.0'],