Sliding Sync: No need to sort if the range is large enough to cover all of the rooms

[MadLittleMods]

No need to sort if the range is large enough to cover all of the rooms in the list. Previously, we would only do this optimization if the range was exactly large enough.

Follow-up to #17672

Pull Request Checklist

• Pull request is based on the develop branch
• Pull request includes a changelog file. The entry should:
  • Be a short description of your change which makes sense to users. "Fixed a bug that prevented receiving messages from other servers." instead of "Moved X method from EventStore to EventWorkerStore.".
  • Use markdown where necessary, mostly for code blocks.
  • End with either a period (.) or an exclamation mark (!).
  • Start with a capital letter.
  • Feel free to credit yourself, by adding a sentence "Contributed by @github_username." or "Contributed by [Your Name]." to the end of the entry.
• Code style is correct
  (run the linters)