thread summary: disappear in tombstoned rooms?

[bnjbvr]

We had a report that a tombstoned room may lose its thread summaries 👀

[jmartinesp]

FTR this was after enabling the feature in the developer settings, clearing the cache, then restarting the app so the feature is actually enabled from the ClientBuilder.

Reseting the cache again fixed the issue, so I can't reproduce it anymore 🫤 .

[manuroe]

It is a valid request to ask apps to reset the cache when enabling a feature, especially a big one like threads.

[bnjbvr]

I don't think we should have to clear the cache, in this case.

That being said, it's possible, considering all the other bugs filed in the parent issue, that we're overwriting the thread summary that's stored in the DB, under some peculiar occasions. That would explain incorrect latest events in a few situations, including this one.