Build: Use deterministic module ids in webpack for media

Follow-up for [50940].
Props peterwilsoncc.
See #53192. 



git-svn-id: https://develop.svn.wordpress.org/trunk@50984 602fd350-edb4-49c9-b593-d223f7449a82

tools/webpack/media.js

@@ -27,6 +27,7 @@ module.exports = function( env = { environment: 'production', watch: false, buil
 		},
 		optimization: {
 			minimize: true,
+			moduleIds: 'named',
 			minimizer: [
 				new UglifyJsPlugin( {
 					include: /\.min\.js$/,