MSC4140: don't cancel delayed state on own state

[AndrewFerr]

When a user sends a state event, do not cancel their own delayed events for the same piece of state.

For context, see the relevant section in the MSC.

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.
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• Code style is correct
  (run the linters)

[AndrewFerr]

Depends on matrix-org/complement#742 for Complement tests to pass.

[anoadragon453]

Looks good on the whole, just some small points of feedback.

[anoadragon453]

Out of interest, would it be worth instead adding an argument to get_partial_current_state_deltas to filter out state deltas that do not have an associated event ID?

[AndrewFerr]

That would be helpful, yes. Since that's not strictly required for this PR, though, I opened a new one for it: #17833

[AndrewFerr]

It was decided out-of-band to not pursue adding that argument, so let's leave this as it is.

[AndrewFerr]

The sytests pass when I run them locally. Is there a way to retry their CI runs?

[MadLittleMods]

@AndrewFerr Retried 👍

[AndrewFerr]

Now the only failing tests are the ones that depend on matrix-org/complement#742 (finally!).