feat(iOS): add-javaScriptEnabled prop (#592)

* add-javaScriptEnabled-in-IOS

* Update WebViewTypes.ts

ios/RNCWKWebView.h

 @property (nonatomic, copy) NSString *userAgent;
 @property (nonatomic, copy) NSString *applicationNameForUserAgent;
 @property (nonatomic, assign) BOOL cacheEnabled;
+@property (nonatomic, assign) BOOL javaScriptEnabled;
 @property (nonatomic, assign) BOOL allowsLinkPreview;
 @property (nonatomic, assign) BOOL showsHorizontalScrollIndicator;
 @property (nonatomic, assign) BOOL showsVerticalScrollIndicator;

ios/RNCWKWebView.m

 {
   if (self.window != nil && _webView == nil) {
     WKWebViewConfiguration *wkWebViewConfig = [WKWebViewConfiguration new];
+    WKPreferences *prefs = [[WKPreferences alloc]init];
+    if (!_javaScriptEnabled) {
+      prefs.javaScriptEnabled = NO;
+      wkWebViewConfig.preferences = prefs;
+    }
     if (_incognito) {
       wkWebViewConfig.websiteDataStore = [WKWebsiteDataStore nonPersistentDataStore];
     } else if (_cacheEnabled) {

src/WebView.ios.tsx

 class WebView extends React.Component<IOSWebViewProps, State> {
   static defaultProps = {
     useWebKit: true,
+    javaScriptEnabled: true,
     cacheEnabled: true,
     originWhitelist: defaultOriginWhitelist,
     useSharedProcessPool: true,

src/WebViewTypes.ts

    */
   urlPrefixesForDefaultIntent?: ReadonlyArray<string>;
 
-  /**
-   * Boolean value to enable JavaScript in the `WebView`. Used on Android only
-   * as JavaScript is enabled by default on iOS. The default value is `true`.
-   * @platform android
-   */
-  javaScriptEnabled?: boolean;
-
   /**
    * Boolean value to disable Hardware Acceleration in the `WebView`. Used on Android only
    * as Hardware Acceleration is a feature only for Android. The default value is `false`.
    */
   source?: WebViewSource;
 
+  /**
+   * Boolean value to enable JavaScript in the `WebView`. Used on Android only
+   * as JavaScript is enabled by default on iOS. The default value is `true`.
+   * @platform android
+   */
+  javaScriptEnabled?: boolean;
+  
   /**
    * Function that returns a view to show if there's an error.
    */