chore(firestore): move example app to "flutterfire-e2e-test" project (#10036)

Author: russellwheatley

packages/cloud_firestore/cloud_firestore/example/android/app/build.gradle

@@ -22,6 +22,9 @@ if (flutterVersionName == null) {
 }
 
 apply plugin: 'com.android.application'
+// START: FlutterFire Configuration
+apply plugin: 'com.google.gms.google-services'
+// END: FlutterFire Configuration
 apply plugin: 'kotlin-android'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
@@ -43,7 +46,7 @@ android {
 
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
-        applicationId "io.flutter.plugins.firebase.firestoreexample"
+        applicationId "io.flutter.plugins.firebase.firestore.example"
         minSdkVersion 19
         targetSdkVersion flutter.targetSdkVersion
         versionCode flutterVersionCode.toInteger()