* Include expiration time in `LoggedInUser`
This will allow the profile watcher to detect when the user relogged.
* Display expiration time in UI
* Add `ClearStaleClusterClients` RPC
* Implement `ClearStaleClusterClients`
* Clear stale clients when profile changes
* Improve session expiration component
* Move refresh button back to top
* `ClearCachedStaleClientsForRoot` -> `ClearStaleCachedClientsForRoot`
* `unchanged` -> `stale`
* Make "closing stale clients" a subtest
* Add `clientcache` test
* Remove `getProfile` error wrapping
* Improve comment
* Convert story to controls