Remove legacy tooltip code

app/assets/javascripts/projects/settings_service_desk/components/service_desk_setting.vue

 <script>
 import { GlButton, GlFormSelect, GlToggle, GlLoadingIcon, GlSprintf } from '@gitlab/ui';
 import { __ } from '~/locale';
-import tooltip from '~/vue_shared/directives/tooltip';
 import glFeatureFlagsMixin from '~/vue_shared/mixins/gl_feature_flags_mixin';
 import ClipboardButton from '~/vue_shared/components/clipboard_button.vue';
 import eventHub from '../event_hub';
 
 export default {
   name: 'ServiceDeskSetting',
-  directives: {
-    tooltip,
-  },
   components: {
     ClipboardButton,
     GlButton,