Pass accessibilityHint through Button component

Summary:
Changelog: [Internal]

Previously, the `accessibilityHint` value isn't passed through the underlying component so that the voice over system doesn't announce it. This diff fixes that.

Reviewed By: sammy-SC

Differential Revision: D31017275

fbshipit-source-id: 1bf5a5e36fdfed2a199986b82684a40e18325ba1

Libraries/Components/Button.js

@@ -145,6 +145,7 @@ type ButtonProps = $ReadOnly<{|
   accessibilityActions?: ?$ReadOnlyArray<AccessibilityActionInfo>,
   onAccessibilityAction?: ?(event: AccessibilityActionEvent) => mixed,
   accessibilityState?: ?AccessibilityState,
+  accessibilityHint?: ?string,
 |}>;
 
 /**
@@ -275,6 +276,7 @@ class Button extends React.Component<ButtonProps> {
       testID,
       accessible,
       accessibilityActions,
+      accessibilityHint,
       onAccessibilityAction,
     } = this.props;
     const buttonStyles = [styles.button];
@@ -317,6 +319,7 @@ class Button extends React.Component<ButtonProps> {
         accessibilityActions={accessibilityActions}
         onAccessibilityAction={onAccessibilityAction}
         accessibilityLabel={accessibilityLabel}
+        accessibilityHint={accessibilityHint}
         accessibilityRole="button"
         accessibilityState={accessibilityState}
         hasTVPreferredFocus={hasTVPreferredFocus}