Resolve "Group validation fails incorrectly when descendants have permanent redirects"

What does this MR do?

• Improves ensure_permanent_paths group validation to not fail if the Group have descendants with permanent redirects

• Refactor Route callbacks

Why was this MR needed?

Because it's not allowed to reclaim an old namespace even if it's the original owner

Does this MR meet the acceptance criteria?

• Documentation created/updated
• Tests added for this feature/bug
• Review
  • Has been reviewed by Backend
• Conform by the merge request performance guides
• Conform by the style guides

What are the relevant issue numbers?

Closes #41935 (closed)