Add snapToAlignment to ScrollView.js Android implementation

Summary:
Update ScrollView.js to support snapToAlignment in RN Android

changelog: [Android][Added] Implement snapToAlignment in ReactHorizontalScrollView

Reviewed By: JoshuaGross

Differential Revision: D31174546

fbshipit-source-id: 480e990793ced74121c6aa1875f2695a70d1f804

Author: mdvacca

Libraries/Components/ScrollView/ScrollView.js

@@ -346,17 +346,6 @@ type IOSProps = $ReadOnly<{|
    * The default value is true.
    */
   showsHorizontalScrollIndicator?: ?boolean,
-  /**
-   * When `snapToInterval` is set, `snapToAlignment` will define the relationship
-   * of the snapping to the scroll view.
-   *
-   *   - `'start'` (the default) will align the snap at the left (horizontal) or top (vertical)
-   *   - `'center'` will align the snap in the center
-   *   - `'end'` will align the snap at the right (horizontal) or bottom (vertical)
-   *
-   * @platform ios
-   */
-  snapToAlignment?: ?('start' | 'center' | 'end'),
   /**
    * The current scale of the scroll view content. The default value is 1.0.
    * @platform ios
@@ -597,6 +586,15 @@ export type Props = $ReadOnly<{|
    * for example when you want your list to have an animated hidable header.
    */
   StickyHeaderComponent?: StickyHeaderComponentType,
+  /**
+   * When `snapToInterval` is set, `snapToAlignment` will define the relationship
+   * of the snapping to the scroll view.
+   *
+   *   - `'start'` (the default) will align the snap at the left (horizontal) or top (vertical)
+   *   - `'center'` will align the snap in the center
+   *   - `'end'` will align the snap at the right (horizontal) or bottom (vertical)
+   */
+  snapToAlignment?: ?('start' | 'center' | 'end'),
   /**
    * When set, causes the scroll view to stop at multiples of the value of
    * `snapToInterval`. This can be used for paginating through children