Remove redundant Vuex includes in approvals module

ee/app/assets/javascripts/approvals/mount_mr_edit.js

 import Vue from 'vue';
-import Vuex from 'vuex';
 import { parseBoolean } from '~/lib/utils/common_utils';
 import MrEditApp from './components/mr_edit/app.vue';
 import createStore from './stores';
 import mrEditModule from './stores/modules/mr_edit';
 
-Vue.use(Vuex);
-
 export default function mountApprovalInput(el) {
   if (!el) {
     return null;

ee/app/assets/javascripts/approvals/mount_project_settings.js

 import Vue from 'vue';
-import Vuex from 'vuex';
 import { parseBoolean } from '~/lib/utils/common_utils';
 import ProjectSettingsApp from './components/project_settings/app.vue';
 import createStore from './stores';
 import projectSettingsModule from './stores/modules/project_settings';
 
-Vue.use(Vuex);
-
 export default function mountProjectSettingsApprovals(el) {
   if (!el) {
     return null;