Fix setLocationShared for Wrapper SDK's (#403)

• Most OneSignal Wrapper SDK's call init() twice, the first time calls it with a nil appID as the first initialization step, and then init() gets called later on as the wrapper runtime (ie. the React Native runtime) is loaded and initialized
• The problem with this approach is that the SDK also checks to see if it should start sharing location in init()
• So when init() gets called automatically with a nil app ID by wrapper SDK's (before the runtime is loaded), the SDK started sharing location
• This meant location was shared even if developers later on called setLocationShared(false), even if they call it before they called init() with their app ID
• This commit fixes the issue by checking to make sure the app ID exists before checking if it should share location
• Init needs to be refactored in general to be simpler, but this should work as a quick fix.

iOS_SDK/OneSignalSDK/Source/OneSignal.m

@@ -423,7 +423,7 @@ + (id)initWithLaunchOptions:(NSDictionary*)launchOptions appId:(NSString*)appId
     if (!success)
         return self;
 
-    if (mShareLocation)
+    if (appId && mShareLocation)
        [OneSignalLocation getLocation:false];
 
     if (self) {