removed tabbar for iOS 9 compatibility issues

Summary: Removed Accessibility Trait TabBar for iOS compatibility Issues, since tabbar is only available on iOS 10+

Reviewed By: PeteTheHeat

Differential Revision: D8822469

fbshipit-source-id: 34bf00eb930f631a5a4effa0a4159da07c1573f6

Libraries/Components/View/ViewAccessibility.js

@@ -44,8 +44,7 @@ export type AccessibilityRole =
   | 'button'
   | 'image'
   | 'keyboardkey'
-  | 'text'
-  | 'tabbar';
+  | 'text';
 
 module.exports = {
   AccessibilityTraits: [
@@ -79,6 +78,5 @@ module.exports = {
     'image',
     'keyboardkey',
     'text',
-    'tabbar',
   ],
 };