Clean unused import modules.

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Closes https://github.com/facebook/react-native/pull/10413

Differential Revision: D4028108

fbshipit-source-id: 99a864dfda578d640f582b296583591415ba26cd

Examples/UIExplorer/js/UIExplorerExampleContainer.js

@@ -29,8 +29,6 @@ const {
 const UIExplorerBlock = require('./UIExplorerBlock');
 const UIExplorerPage = require('./UIExplorerPage');
 
-const invariant = require('fbjs/lib/invariant');
-
 class UIExplorerExampleContainer extends React.Component {
   renderExample(example, i) {
     // Filter platform-specific examples