Parity of response format

Author: chaitanya-bhagavan

ios/Firestack/FirestackAuth.m

@@ -187,14 +187,15 @@ @implementation FirestackAuth
 
  if (user != nil) {
  NSDictionary *userProps = [self userPropsFromFIRUser:user];
- NSMutableDictionary *responseProps = @{
+ NSDictionary *responseProps = @{
  @"authenticated": @((BOOL) true),
  @"user": userProps
  };
  callback(@[[NSNull null], responseProps]);
  } else {
  // No user is signed in.
  NSDictionary *err = @{
+ @"authenticated": @((BOOL) false),
  @"user": @"No user logged in"
  };
  callback(@[err]);