Add testing library commands to be used in Cypress tests

This PR adds @cypress/testing-library to add Testing Library queries. I only converted one test to give a small flavour of what to expect.

By using the TL queries, we can rely less on artificial data-cy attributes but rather on the intrinsic roles and labels of elements, to be closer from the actual user experience.

Also, this will help improving the accessibility by sanitizing the DOM and strengthen the Cypress to avoid random failures (hopefully 🤞 ).