Might as well inline, but I feel like it will require adding the same
comment across all usages, because just `State.Value = Hidden` in an
until step feels off, dunno.
The test was checking the test scene's own `SelectedMods` bindable
rather than the multiplayer screen's, and the former was never actually
being mutated by anything. Therefore the case would pass even on
`master` with the fix reverted.