Fix iOS remove email and remove sms methods

Call arguments for remove email and remove sms do not have defined keys in user.dart and calling with a key returns an error on iOS

Author: shepherd-l

ios/Classes/OSFlutterUser.m

@@ -109,7 +109,7 @@ - (void)addEmail:(FlutterMethodCall *)call withResult:(FlutterResult)result {
 }
 
 - (void)removeEmail:(FlutterMethodCall *)call withResult:(FlutterResult)result {
-    NSString *email = call.arguments[@"email"];
+    NSString *email = call.arguments;
     [OneSignal.User removeEmail:email];
     result(nil);
 }
@@ -121,7 +121,7 @@ - (void)addSms:(FlutterMethodCall *)call withResult:(FlutterResult)result {
 }
 
 - (void)removeSms:(FlutterMethodCall *)call withResult:(FlutterResult)result {
-    NSString *smsNumber = call.arguments[@"smsNumber"];
+    NSString *smsNumber = call.arguments;
     [OneSignal.User removeSms:smsNumber];
     result(nil);
 }