Update MR deployment to use .label-truncate with .deploy-link

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

 <script>
 import Icon from '~/vue_shared/components/icon.vue';
+import TooltipOnTruncate from '~/vue_shared/components/tooltip_on_truncate.vue';
 import timeagoMixin from '../../vue_shared/mixins/timeago';
 import tooltip from '../../vue_shared/directives/tooltip';
 import LoadingButton from '../../vue_shared/components/loading_button.vue';
@@ -16,6 +17,7 @@ export default {
     MemoryUsage,
     StatusIcon,
     Icon,
+    TooltipOnTruncate,
   },
   directives: {
     tooltip,
@@ -88,14 +90,20 @@ export default {
               <span>
                 Deployed to
               </span>
+              <tooltip-on-truncate
+                :title="deployment.name"
+                truncate-target="child"
+                class="deploy-link label-truncate"
+              >
                 <a
                   :href="deployment.url"
                   target="_blank"
                   rel="noopener noreferrer nofollow"
-                class="deploy-link js-deploy-meta"
+                  class="js-deploy-meta"
                 >
                   {{ deployment.name }}
                 </a>
+              </tooltip-on-truncate>
             </template>
             <span
               v-tooltip

app/assets/stylesheets/pages/merge_requests.scss

@@ -237,7 +237,10 @@
     font-weight: normal;
     overflow: hidden;
     word-break: break-all;
+  }
 
+  .deploy-link,
+  .label-branch {
     &.label-truncate {
       // NOTE: This selector targets its children because some of the HTML comes from
       // 'source_branch_link'. Once this external HTML is no longer used, we could