Refactor InstallerNonDefaultDatabaseDriverTest to avoid DatabaseDriverUninstallValidator re-fetch the database connection

IMO the test should have not been using the test container, that remains linked to the db driver passed in to the test. Since the essence of the test is to diverge from it in the SUT, let’s check the SUT’s GUI for the modules statuses.

Left a comment in the MR.

Small comment then good to RTBC I think

Ah right.

Then rest seems good

This should be marked 'fixed' now, right?

mondrake → closed merge request !11805

Yes it should, looks like I lost track of the tab...

Committed/pushed to 11.x, thanks!