Migrate MR source branch deletion tooltip to GitLab UI

app/assets/javascripts/vue_merge_request_widget/components/source_branch_removal_status.vue

 <script>
-import { GlIcon, GlSprintf } from '@gitlab/ui';
-import tooltip from '../../vue_shared/directives/tooltip';
+import { GlIcon, GlSprintf, GlTooltipDirective } from '@gitlab/ui';
 import { __ } from '../../locale';
 
 export default {
@@ -13,7 +12,7 @@ export default {
     GlSprintf,
   },
   directives: {
-    tooltip,
+    GlTooltip: GlTooltipDirective,
   },
 };
 </script>
@@ -28,7 +27,7 @@ export default {
       </gl-sprintf>
     </span>
     <gl-icon
-      v-tooltip
+      v-gl-tooltip.hover
       :title="$options.i18n.tooltipTitle"
       :aria-label="$options.i18n.tooltipTitle"
       name="question-o"

ee/spec/frontend/vue_mr_widget/ee_mr_widget_options_spec.js

@@ -962,7 +962,7 @@ describe('ee merge request widget options', () => {
         const tooltip = vm.$el.querySelector('[data-testid="question-o-icon"]');
 
         expect(vm.$el.textContent).toContain('Deletes source branch');
-        expect(tooltip.getAttribute('data-original-title')).toBe(
+        expect(tooltip.getAttribute('title')).toBe(
           'A user with write access to the source branch selected this option',
         );
 

spec/frontend/vue_mr_widget/mr_widget_options_spec.js

@@ -536,7 +536,7 @@ describe('mrWidgetOptions', () => {
           const tooltip = vm.$el.querySelector('[data-testid="question-o-icon"]');
 
           expect(vm.$el.textContent).toContain('Deletes source branch');
-          expect(tooltip.getAttribute('data-original-title')).toBe(
+          expect(tooltip.getAttribute('title')).toBe(
             'A user with write access to the source branch selected this option',
           );