Replace mountComponent with mount

spec/frontend/pipelines/blank_state_spec.js

-import Vue from 'vue';
-import mountComponent from 'helpers/vue_mount_component_helper';
-import component from '~/pipelines/components/pipelines_list/blank_state.vue';
+import { mount } from '@vue/test-utils';
+import { getByText } from '@testing-library/dom';
+import BlankState from '~/pipelines/components/pipelines_list/blank_state.vue';
 
 describe('Pipelines Blank State', () => {
-  let vm;
-  let Component;
-
-  beforeEach(() => {
-    Component = Vue.extend(component);
-
-    vm = mountComponent(Component, {
+  const wrapper = mount(BlankState, {
+    propsData: {
       svgPath: 'foo',
       message: 'Blank State',
-    });
+    },
   });
 
   it('should render svg', () => {
-    expect(vm.$el.querySelector('.svg-content img').getAttribute('src')).toEqual('foo');
+    expect(wrapper.find('.svg-content img').attributes('src')).toEqual('foo');
   });
 
   it('should render message', () => {
-    expect(vm.$el.querySelector('h4').textContent.trim()).toEqual('Blank State');
+    expect(getByText(wrapper.element, /Blank State/i)).toBeTruthy();
   });
 });