Fix Keybindings not shown on mania scroll speed change

[AdrianEdelen]

closes #15211

This is my first contribution to osu!, so I searched for a ticket that had a simple MVP solution to get some practice contributing.

The issue also mentions a possible refactor/cleanup, I considered something like injecting RealmKeyBindingStore in RulesetConfigManager or expanding IRulesetConfigManager to have a method that can look up the keybind, but figured that those are slightly bigger architectural changes, and didn't want to overstep my first contribution as I am still learning the codebase.

for this change, I decided to use a similar implementation as OsuGameBase as an MVP fix. and lifted LookupKeyBindings from OsuConfigManager

Here is in OsuConfigManager that I based my implementation on

osu/osu.Game/Configuration/OsuConfigManager.cs

Lines 283 to 287 in 4f649c5

	shortcut: new TranslatableString(@"_", @"{0}: {1} {2}: {3}",
	GlobalActionKeyBindingStrings.ToggleInGameInterface,
	LookupKeyBindings(GlobalAction.ToggleInGameInterface),
	GlobalActionKeyBindingStrings.HoldForHUD,
	LookupKeyBindings(GlobalAction.HoldForHUD)))

and in DrawableManiaRuleset.cs I used the following from OsuGameBase.cs

osu/osu.Game/OsuGameBase.cs

Line 440 in 4f649c5

LocalConfig.LookupKeyBindings = l => KeyBindingStore.GetBindingsStringFor(l);

First image is showing the change running in debug, and the second is a visual test confirming behavior.