fix(unit-jest): fix .vue coverage report when babel plugin is not enabled (#5499)

Author: haoqunjiang

packages/@vue/cli-plugin-unit-jest/__tests__/jestPlugin.spec.js

@@ -66,6 +66,10 @@ test('should work without Babel', async () => {
     useConfigFiles: true
   })
   await project.run(`vue-cli-service test:unit`)
+
+  await project.run(`vue-cli-service test:unit --coverage --collectCoverageFrom="src/**/*.{js,vue}"`)
+  const appCoverage = await project.read('coverage/lcov-report/App.vue.html')
+  expect(appCoverage).toBeTruthy()
 })
 
 test('should work with tsx', async () => {

packages/@vue/cli-plugin-unit-jest/presets/no-babel/jest-preset.js

@@ -13,7 +13,7 @@ module.exports = deepmerge(
     globals: {
       'vue-jest': {
         babelConfig: {
-          plugins: [require('babel-plugin-transform-es2015-modules-commonjs')]
+          plugins: ['babel-plugin-transform-es2015-modules-commonjs']
         }
       }
     }