Flow strict StaticContainer (#22121)

Summary:
Related to #22100

Turn on Flow strict mode for StaticContainer.react
This component needed proper Props type definition. I went through the only component (`TabBarItemIOS.ios`) using this to try to know the most appropriate props.

- All flow tests succeed.

[GENERAL] [ENHANCEMENT] [StaticContainer.react.js] - Flow strict mode
Pull Request resolved: https://github.com/facebook/react-native/pull/22121

Differential Revision: D12929646

Pulled By: TheSavior

fbshipit-source-id: 8826aa7bc83c854efdd71cdb4fba3d7ca98f2fce

Libraries/Components/StaticContainer.react.js

@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  *
  * @format
- * @flow
+ * @flow strict-local
  */
 
 'use strict';
@@ -27,8 +27,19 @@ const React = require('React');
  * Typically, you will not need to use this component and should opt for normal
  * React reconciliation.
  */
-class StaticContainer extends React.Component<Object> {
-  shouldComponentUpdate(nextProps: Object): boolean {
+
+type Props = $ReadOnly<{|
+  /**
+   * Whether or not this component should update.
+   */
+  shouldUpdate: ?boolean,
+  /**
+   * Content short-circuited by React reconciliation process.
+   */
+  children: React.Node,
+|}>;
+class StaticContainer extends React.Component<Props> {
+  shouldComponentUpdate(nextProps: Props): boolean {
     return !!nextProps.shouldUpdate;
   }