Update ExtraConstants.java (#5)

Author: SUPERCILEX

auth/src/main/java/com/firebase/ui/auth/ui/ExtraConstants.java

@@ -19,7 +19,6 @@
  */
 public class ExtraConstants {
     public static final String EXTRA_EMAIL = "extra_email";
-    public static final String EXTRA_NAME = "extra_name";
     public static final String EXTRA_USER = "extra_user";
     public static final String EXTRA_ERROR_MESSAGE = "extra_error_msg";
     public static final String EXTRA_FLOW_PARAMS = "extra_flow_params";