Backport 'Provision inherited foundational flows without user elevation' to 19-3-stable-ee

What does this MR do and why?

Backport of !249053 (merged) ("Provision inherited foundational flows without user elevation") to the 19-3-stable-ee branch.

Projects that inherit foundational flows are synchronized during project creation and after import. That synchronization currently runs as the initiating user, so a project created by a Developer is rejected by Maintainer-level consumer and trigger checks even though the root group has already enabled the flow.

This MR cherry-picks all 9 commits from the original MR onto 19-3-stable-ee. All commits applied cleanly with no conflicts.

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, request help in the #s_developer_experience Slack channel to confirm the failures are unrelated to the merge request.

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.

References

Backport of !249053 (merged) Closes https://gitlab.com/gitlab-org/gitlab/-/issues/606415