Update E2E Testing Docs
What does this MR do and why?
Updates E2E testing docs to reflect that data-testid
elements now use kebab-case
strings and remove references to our Sauce Labs mobile suite as it no longer exists.
Related to gitlab-org/quality/quality-engineering/team-tasks#2324 (closed) & https://gitlab.com/gitlab-com/gitlab-OKRs/-/work_items/6491
MR acceptance checklist
Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.
Edited by Désirée Chevalier