Allow any key to trigger the osu! cookie in the initial state

[Susko3]

Resolves #17854.

Works really wells since GlobalActions are handled with priority. If they weren't, handling all keys would prevent from exiting as it would consume the Escape/back key.

Full OsuGame tests are added to ensure this behaviour isn't broken in the future by the 'eventual solution':

osu/osu.Game/Input/Bindings/GlobalActionContainer.cs

Lines 131 to 135 in 866ae34

	// To ensure the global actions are handled with priority, this GlobalActionContainer is actually placed after game content.
	// It does not contain children as expected, so we need to forward the NonPositionalInputQueue from the parent input manager to correctly
	// allow the whole game to handle these actions.
	// An eventual solution to this hack is to create localised action containers for individual components like SongSelect, but this will take some rearranging.

[bdach]

I guess this works

[bdach]

I'll note that TestSceneScreenNavigation already exists, is a OsuGameTestScene, and these test cases would fit there, so I'm not sure this needs to be a test scene on its own. Although that is a bit of a mixed bag of tests right now.