add @flow back to View.js

Summary:
looks like @flow got dropped in a diff that
just added comments. Assuming that was inadvertent -
if it was on purpose just LMK and I'll abandon.

Test Plan: flow check

Libraries/Components/View/View.js

@@ -7,6 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *
  * @providesModule View
+ * @flow
  */
 'use strict';