Migrate EE Projects QA selectors to testid

What does this MR do and why?

Migrates some data-qa-selector attributes to be data-testid as per gitlab-org/quality/quality-engineering/team-tasks#1822 (closed)

How to set up and validate locally

Test affected E2E spec:

CHROME_HEADLESS=false bundle exec bin/qa Test::Instance::All http://gdk.test:3000/ ./qa/specs/features/ee/browser_ui/3_create/repository/file_locking_spec.rb

Also note results of Allure reports, should be passing / known unrelated failures.

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.