Backport of Fix flaky new_project_spec CI/CD from repo URL test to 18-11

What does this MR do and why?

Describe in detail what merge request is being backported and why

Backports Fix flaky new_project_spec CI/CD from repo URL ... (!235439 - merged) into 18-11-stable-ee

Please Note: The changes on master only touch 2 tests (the "creates CI/CD project from repo URL" and the "creates a new project in personal namespace" tests).

This backport touches 3 tests — it also fixes the "Import project" tab creates projects with features enabled test.

On master, that test was refactored in a prior MR. It uses fill_in 'project[name]' and has a simpler structure.

On 18-11-stable-ee, the test still has the older form using fill_in 'project_name', namespace picker, visibility selector. So this backport needs to fix that test too, since it still has the same race condition.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• This MR is backporting a bug fix, documentation update, or spec fix, previously merged in the default branch.
• The MR that fixed the bug on the default branch has been deployed to GitLab.com (not applicable for documentation or spec changes).
• The MR title is descriptive (e.g. "Backport of 'title of default branch MR'"). This is important, since the title will be copied to the patch blog post.
• Required labels have been applied to this merge request
  • severity label and bug subtype labels (if applicable)
  • If this MR fixes a bug that affects customers, the customer label has been applied.
• This MR has been approved by a maintainer (only one approval is required).
• Ensure the e2e:test-on-omnibus-ee job has succeeded, or if it has failed, investigate the failures. If you determine the failures are unrelated, you may proceed. If you need assistance investigating, reach out to a Software Engineer in Test in #s_developer_experience.

Note to the merge request author and maintainer

If you have questions about the patch release process, please:

• Refer to the patch release runbook for engineers and maintainers for guidance.
• Ask questions on the #releases Slack channel (internal only).
• Once the backport has been merged, the commit changes will be automatically deployed to a release environment that can be used for manual validation. See after merging runbook for details.