feat: add rooms.join endpoint for all room types - #40996

Conclusion: success

Steps

• ✅ No merge conflicts
• ✅ QA assured
• ✅ Mergeable
• ✅ Has milestone or project
• ✅ Valid PR title
• ✅ Correct target version

Merge

⚠️ All merge strategies failed
❌ Enqueue: Request failed due to following response errors:

• Pull request All comments must be resolved. 1 review requesting changes and 1 approving review by reviewers with write access. — Pull request All comments must be resolved. 1 review requesting changes and 1 approving review by reviewers with write access.
  ❌ Auto-merge: Request failed due to following response errors:
• Auto merge is not allowed for this repository — Auto merge is not allowed for this repository
  ❌ Squash merge: status=405 — Changes must be made through the merge queue All comments must be resolved. 1 review requesting changes and 1 approving review by reviewers with write access. - https://docs.github.com/articles/about-protected-branches