Fixed crash on iOS/Updated lib to 1.2.1

Author: yarikpwnzer

ios/RNSurveyMonkeyView.m

@@ -4,9 +4,12 @@
 #import <SurveyMonkeyiOSSDK/SurveyMonkeyiOSSDK.h>
 
 static NSDictionary *SurveyMonkeyErrorJson(NSError *error) {
+  NSDictionary *userInfo = error.userInfo;
+  BOOL surveyError = userInfo[@"SurveyMonkeySDK_Error"];
+  NSString *errorDescription = surveyError ? error.userInfo[@"SurveyMonkeySDK_Error"] : error.localizedDescription;
   return @{
     @"code": @(error.code),
-    @"description": error.userInfo[@"SurveyMonkeySDK_Error"],
+    @"description": errorDescription,
     @"fullDescription": error.description
   };
 }

package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-native-survey-monkey",
-  "version": "1.2.0",
+  "version": "1.2.1",
   "description": "React Native library for Survey Monkey",
   "contributors": [
     "Yaroslav Fuchko <yarikpwnzer1@gmail.com>",