remove test for internal detail of ItemDueDate component

spec/frontend/vue_shared/components/issue/related_issuable_item_spec.js

@@ -144,23 +144,6 @@ describe('RelatedIssuableItem', () => {
 
       expect(wrapper.find(IssueDueDate).props('closed')).toBe(true);
     });
-
-    it('should not contain the `.text-danger` css class for overdue issue that is closed', async () => {
-      mountComponent({
-        props: {
-          ...props,
-          closedAt: '2018-12-01T00:00:00.00Z',
-        },
-      });
-      await wrapper.vm.$nextTick();
-
-      expect(wrapper.find(IssueDueDate).find('.board-card-info-icon').classes('text-danger')).toBe(
-        false,
-      );
-      expect(wrapper.find(IssueDueDate).find('.board-card-info-text').classes('text-danger')).toBe(
-        false,
-      );
-    });
   });
 
   describe('token assignees', () => {