(ios) Fixes #566

Prevents closing pagesheet by swiping down, which led to unresponsive app

src/ios/CDVWKInAppBrowser.m

@@ -713,6 +713,8 @@ BOOL isExiting = FALSE;
         [self.webViewUIDelegate setViewController:self];
         
         [self createViews];
+        
+        self.modalInPopover = TRUE;
     }
     
     return self;