[ReactNative] Fix RootContentView release when the top-level bridge is held

Summary:
The RCTRootView creates a underlying RCTRootContentView that was deallocated when
the bridge modules were deallocated. That doesn't work when the bridge is held.

@public

Test Plan:
Launch Groups, put a breakpoint on `-[RCTRootContentView dealloc]`, enter and
leave a group page. It should be called now.

React/Modules/RCTUIManager.m

@@ -281,7 +281,7 @@ static NSDictionary *RCTViewConfigForModule(Class managerClass, NSString *viewNa
 
   dispatch_async(dispatch_get_main_queue(), ^{
     for (NSNumber *rootViewTag in _rootViewTags) {
-      ((UIView *)_viewRegistry[rootViewTag]).userInteractionEnabled = NO;
+      [_viewRegistry[rootViewTag] invalidate];
     }
 
     _rootViewTags = nil;