Add test summary section to the job section sidebar

What does this MR do and why?

Add the test summary section to the job section sidebar.

The test summary section displays failures or total count depending on whether the job failed or not

#404654 (closed) and possibly #429727 (closed)

Screenshots or screen recordings

How to set up and validate locally

1. Create a project that uses JUnit test reports; here are a few files you can use to create that project

.gitlab-ci.yml

javascript:
  image: node:latest
  stage: test
  before_script:
    - 'yarn global add jest'
    - 'yarn add --dev jest-junit'
  script:
    - 'jest --ci --reporters=default --reporters=jest-junit --passWithNoTests'
  artifacts:
    when: always
    reports:
      junit:
        - junit.xml

jest.config.js

const config = {
  transform: {
    '^.+\\.js$': 'babel-jest',
  },  
}

module.exports = config;

sum.js

function sum(a, b) {
  return a + b;
}

module.exports = sum;

sum.test.js

const sum = require('./sum');

test('adds 1 + 2 to equal 3', () => {
  expect(sum(1, 2)).toBe(3);
});

2. Create a pipeline and wait for it to finish
3. Look at the sidebar and the test summary should display

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.