* MatrixChat: add a load of logging for view transitions
This stuff was essentially impossible to follow and debug. I think a load of
logging will help.
* Add more comments on `state.view`
* Add a new state between LOADING/SOFT_LOGOUT and LOGGED_IN
... so that we can transition into COMPLETE_SECURITY without going via
LOGGED_IN.
* Remove redundant check for `force_verification`
This check was previously necessary to keep the tests working, because:
* onLoggedIn would call `onShowPostLoginScreen`,
* which (without the check) would call `showScreenAfterLogin`
* which would queue up an action `Action.ViewHomePage`
* Then we would receive an already-queued `ClientStarted` action, which would
transition us (correctly) to the `COMPLETE_SECURITY` view
* Then we would receive the `ViewHomePage` action, taking us back to `LOGGED_IN`.
I don't think the check was necessary in practice, because in practice there
would be enough delay between the OnLoggedIn and ClientStarted actions that the
race didn't happen.
The *problem* with the check was that it meant that, whenever
`force_verification` was enabled, we would get stuck in the LOADING state.
The check is now unnecessary, because `onLoggedIn` no longer calls
`onShowPostLoginScreen`.
* `onShowPostLoginScreen` need no longer be `async`
* Regression test for https://github.com/element-hq/element-web/issues/31203
04cf53e7aa