Fix Issue 10718: Add iOS support for progressViewOffset (#30737)

Summary:
Fixes https://github.com/facebook/react-native/issues/10718, bringing `progressViewOffset` support to iOS.

Thanks to Taylor123 for the initial PR upon which this fix is based.

## Changelog

[iOS] [Fix] - `progressViewOffset` prop of `RefreshControl` and `VirtualizedList` now works on iOS

Pull Request resolved: https://github.com/facebook/react-native/pull/30737

Test Plan:
Tested with quick-and-dirty sample app.

![progressViewOffset-iOS](https://user-images.githubusercontent.com/1563532/104526540-82fe1d80-55b7-11eb-9f99-e025bedf4874.gif)

## Documentation

The corresponding documentation update PR can be found [here](https://github.com/facebook/react-native-website/pull/2441).

Reviewed By: kacieb

Differential Revision: D26813977

Pulled By: sammy-SC

fbshipit-source-id: 45cc5a647d70e44a29c6391b7586cb41ca011bef

Libraries/Components/RefreshControl/RefreshControl.js

@@ -52,10 +52,6 @@ type AndroidProps = $ReadOnly<{|
    * Size of the refresh indicator.
    */
   size?: ?('default' | 'large'),
-  /**
-   * Progress view top offset
-   */
-  progressViewOffset?: ?number,
 |}>;
 
 export type RefreshControlProps = $ReadOnly<{|
@@ -72,6 +68,11 @@ export type RefreshControlProps = $ReadOnly<{|
    * Whether the view should be indicating an active refresh.
    */
   refreshing: boolean,
+
+  /**
+   * Progress view top offset
+   */
+  progressViewOffset?: ?number,
 |}>;
 
 /**
@@ -162,7 +163,6 @@ class RefreshControl extends React.Component<RefreshControlProps> {
         colors,
         progressBackgroundColor,
         size,
-        progressViewOffset,
         ...props
       } = this.props;
       return (