Default app state inaccurate while syncing

[nadonomy]

Steps to reproduce

Sync a large account. Observe the client shows misleading content to the user as if their rooms/account don't exist at all:

Reported by @InezMc

Outcome

We shouldn't display content which misleads the user into thinking all their data may be missing. We should indicate loading consistently as some tabs show a spinner and others don't.

Your phone model

No response

Operating system version

No response

Application version

No response

Homeserver

No response

Will you send logs?

No

[nadonomy]

Related: @BillCarsonFr also notes the left panel loading state needs attention too as it's equally misleading/can lack spaces.

If we're syncing a large account I wonder if we should use a loading state for the entire app?

[BillCarsonFr]

Also notice that it's a regular incremental sync after opening the app (not an initial sync).
I initialy thought that it was related to space hierachy (?) beeing very slow to resolve (or failing?) thus preventing the home to display known rooms as it doesn't now what to show (as it should be filtered by a space)

[InezMc]

It was odd /unexpected as I had been using the app throughout the day and this occured at the end of the day. So it was not due to opening the app after a few days or hours. It may be explained by me closing the app and then restarting.

[thibaultamartin]

It happens to me fairly regularly, I think once in a month on average. I assumed the app was aggressively clearing cache regularly, since the behaviour is very similar when I clear cache

[pixlwave]

This looks as though it is the result of an inconsistency/corruption of the store, at which point the store is reset and an initial sync will take place. It would probably be sensible to get a rageshake linked to the issue to confirm though.

@niquewoodhouse, I seem to remember we discussed about skeleton screens for #4829 but decided there wasn't anywhere they would fit? Maybe that would be the right behaviour when an initial sync is taking place?