[E2E] Dequarantine webide specs in slow network jobs

What does this MR do?

This test was quarantine for slow-network jobs due to failure #387609 (closed). Recently this spec was refactored and its quite stable in master and other environments, so trying to see if the refactor has fixed the issue in slow-network jobs as well

Also removing the old webide spec for upload as its no longer needed

E2E Test Failure issue(s)

#387609 (closed)

How to set up and validate locally

run:

bundle exec rspec ./qa/specs/features/browser_ui/3_create/web_ide/upload_new_file_in_web_ide_spec.rb

Check-list

• General code guidelines check-list
  • Code review guidelines
  • Style guides
• Quarantine test check-list
  • Follow the Quarantining Tests guide.
  • Confirm the test has a quarantine: tag with the specified quarantine type.
  • Note if the test should be quarantined for a specific environment.
  • (Optionally) In case of an emergency (e.g. blocked deployments), consider adding labels to pick into auto-deploy (Pick into auto-deploy priority1 severity1).
• Dequarantine test check-list
  • Follow the Dequarantining Tests guide.
  • Confirm the test consistently passes on the target GitLab environment(s).
• To ensure a faster turnaround, ask in the #quality_maintainers Slack channel for someone to review and merge the merge request, rather than assigning it directly.