migrate projects:merge_requests:index to static bundle

app/assets/javascripts/dispatcher.js

@@ -55,9 +55,6 @@ import SearchAutocomplete from './search_autocomplete';
             .catch(fail);
           break;
         case 'projects:merge_requests:index':
-          import('./pages/projects/merge_requests/index')
-            .then(callDefault)
-            .catch(fail);
           shortcut_handler = true;
           break;
         case 'projects:issues:index':

app/assets/javascripts/pages/projects/merge_requests/index/index.js

@@ -5,9 +5,9 @@ import initFilteredSearch from '~/pages/search/init_filtered_search';
 import { FILTERED_SEARCH } from '~/pages/constants';
 import { ISSUABLE_INDEX } from '~/pages/projects/constants';
 
-export default () => {
+document.addEventListener('DOMContentLoaded', () => {
   initFilteredSearch(FILTERED_SEARCH.MERGE_REQUESTS);
   new IssuableIndex(ISSUABLE_INDEX.MERGE_REQUEST); // eslint-disable-line no-new
   new ShortcutsNavigation(); // eslint-disable-line no-new
   new UsersSelect(); // eslint-disable-line no-new
-};
+});