Add a workaround for the fact that MatrixChat attempts to use React state for
the state of a state machine: a small `sleep` to let the state settle.
As a result, it turns out we may not see the "Syncing..." state, and in general
`waitForSyncAndLoad` doesn't seem to be doing anything useful.
Any UTs for vector-web layer components or functionality should go here.
This used to contain the UTs for notifications before they got moved to react-sdk.