Add jest + react testing library for unit testing

[harsh183]

Jest is an industry standard for react and usually included by default with create react app, and with some effort I was able to add it in for testing out https://github.com/classtranscribe/FrontEnd/pull/801. Usually this is paired with React Testing Library for having nice UI selectors that work well with react.

I can add the following links to the wiki on testing along with a small writeup:

• https://jestjs.io/docs/using-matchers - jest basics
• https://blog.logrocket.com/testing-react-apps-jest-react-testing-library/ - intro tutorial on jest + react
• https://stackoverflow.com/a/62765143 - where to keep test files
• https://kentcdodds.com/blog/common-mistakes-with-react-testing-library#using-get-variants-as-assertions - tips from the library creator
• https://testing-library.com/docs/dom-testing-library/api-accessibility - also has tests for accessibility features
• https://robertmarshall.dev/blog/react-component-props-passed-to-child-jest-unit-test/ - how to mock child components

[angrave]

Merging. It should be possible to now add jest tests check as part of the CI workflow-

https://github.com/classtranscribe/FrontEnd/blob/staging/.github/workflows/ci.yaml