Add Alt + mousewheel volume adjustment on result screens

[Gennadiyev]

A small patch to fix #31860 and match the behaviors with stable.

untitled.mp4

Most of the code is copy-pasted from SongSelect.cs:

osu/osu.Game/Screens/Select/SongSelect.cs

Lines 1142 to 1145 in e9b8154

	// we want to block plain scrolls on the left side so that they don't scroll the carousel,
	// but also we *don't* want to handle scrolls when they're combined with keyboard modifiers
	// as those will usually correspond to other interactions like adjusting volume.
	protected override bool OnScroll(ScrollEvent e) => !e.ControlPressed && !e.AltPressed && !e.ShiftPressed && !e.SuperPressed;

The inserted GlobalScrollAdjustVolume resides in a VerticalScrollContainer, and I do not know whether it is a good practice or not.

[peppy]

I'm just waiting for the day that this is added back on every single screen in the game.