fix(scrollview): Add nullable attribute to scrollView property

CordovaLib/include/Cordova/CDVPlugin.h

@@ -38,7 +38,7 @@ typedef int CDVWebViewNavigationType;
 // the exposed Swift API and marking it as deprecated
 // TODO: Remove in Cordova 9
 @interface UIView (org_apache_cordova_UIView_Extension)
-@property (nonatomic, weak) UIScrollView* scrollView CDV_DEPRECATED(8, "Check for a scrollView property on the view object at runtime and invoke it dynamically.");
+@property (nonatomic, weak, nullable) UIScrollView* scrollView CDV_DEPRECATED(8, "Check for a scrollView property on the view object at runtime and invoke it dynamically.");
 @end
 #endif