Remove js classes from vue component that are not needed in vue component

app/assets/javascripts/vue_shared/components/time_ago_tooltip.vue

@@ -20,12 +20,6 @@ export default {
       default: 'top',
     },
 
-    shortFormat: {
-      type: Boolean,
-      required: false,
-      default: false,
-    },
-
     cssClass: {
       type: String,
       required: false,
@@ -37,18 +31,12 @@ export default {
     tooltipMixin,
     timeagoMixin,
   ],
-
-  computed: {
-    timeagoCssClass() {
-      return this.shortFormat ? 'js-short-timeago' : 'js-timeago';
-    },
-  },
 };
 </script>
 <template>
   <time
-    :class="[timeagoCssClass, cssClass]"
-    class="js-timeago js-timeago-render"
+    :class="cssClass"
+    class="js-vue-timeago"
     :title="tooltipTitle(time)"
     :data-placement="tooltipPlacement"
     data-container="body"

spec/javascripts/vue_shared/components/time_ago_tooltip_spec.js

@@ -22,7 +22,7 @@ describe('Time ago with tooltip component', () => {
     }).$mount();
 
     expect(vm.$el.tagName).toEqual('TIME');
-    expect(vm.$el.classList.contains('js-timeago')).toEqual(true);
+    expect(vm.$el.classList.contains('js-vue-timeago')).toEqual(true);
     expect(
       vm.$el.getAttribute('data-original-title'),
     ).toEqual(gl.utils.formatDate('2017-05-08T14:57:39.781Z'));
@@ -44,17 +44,6 @@ describe('Time ago with tooltip component', () => {
     expect(vm.$el.getAttribute('data-placement')).toEqual('bottom');
   });
 
-  it('should render short format class', () => {
-    vm = new TimeagoTooltip({
-      propsData: {
-        time: '2017-05-08T14:57:39.781Z',
-        shortFormat: true,
-      },
-    }).$mount();
-
-    expect(vm.$el.classList.contains('js-short-timeago')).toEqual(true);
-  });
-
   it('should render provided html class', () => {
     vm = new TimeagoTooltip({
       propsData: {