Update remaining E2E tests to use new runner registration flow

What does this MR do and why?

Summary: Update all E2E tests to use new runner registration flow.

Time Sensitive: Registration tokens being deprecated during 2024-05-06 09:00UTC to 2024-05-08 22:00UTC - Window 3 gitlab-com/Product#13310 (closed). I'm concerned these tests will start to fail.

Details:

• Updates ProjectRunner and GroupRunner to use new runner registration flow
• Updates UserRunners to be compatible with the changes and minimize changes needed to existing tests
• One test run_pipeline_with_manual_jobs_spec.rb needed to be updated that was used to verify the first iteration of these changes under !149645 (merged)
• Removed unused attribute from a couple runner tests: group_runner_status_counts_spec.rb and group_runner_counts_spec.rb
• Note: Created #460396 (closed) to remove deprecated runner registration flow code from E2E test framework

Relates to gitlab-org/quality/quality-engineering/team-tasks#1726 (closed)

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.

How to set up and validate locally

This MR affects all tests that register new runners. You can verify locally by running a tests that use Group Runners and Project Runners respectively, for example:

 # cd qa/ directory
 # Set values for WEBDRIVER_HEADLESS and QA_GITLAB_URL as needed
 bundle exec rspec qa/specs/features/browser_ui/4_verify/runner/register_group_runner_spec.rb # uses a Group Runner
 bundle exec rspec qa/specs/features/browser_ui/4_verify/runner/register_runner_spec.rb # uses a Project Runner