Update idp_button_google.xml

Reverted to use string value from auth strings.xml and not from a dependency

Author: peterhav

auth/src/main/res/layout/idp_button_google.xml

@@ -1,6 +1,6 @@
 <Button
     xmlns:android="http://schemas.android.com/apk/res/android"
     style="@style/FirebaseUI.Button.AccountChooser.GoogleButton"
-    android:text="@string/common_signin_button_text_long"
+    android:text="@string/sign_in_with_google"
     android:id="@+id/google_button"
     />