* This PR provides a fix for the bug reported in [EGD-6081].
The solution adds the `tear_down`-like fixture called after the
problematic tests, that enforce focus on `ApplicationDesktop'`s
main window.
* Additionally similar solution was added to `test_auto_lock`
to restore original (30s) lock timeout.
[EGD-6081]: https://appnroll.atlassian.net/browse/EGD-6081
