Make BaseButton Shortcut feedback togglable

[Spartan322]

Fixes #365

Makes BaseButton::get_draw_mode return DRAW_NORMAL when a shortcut activates the button if toggle_mode is false and shortcut_feedback is false.

Exposed Additions

BaseButton:

@export
var shortcut_feedback : bool = true

func set_shortcut_feedback(value : bool)
func is_shortcut_feedback() -> bool

Test Project:
ButtonShortcutFeedbackDisableTest.zip

[YuriSizov]

Existing behavior is desirable (godotengine/godot-proposals#4936), so this should not be done as a breaking compatibility change and instead should be an option.

[Spartan322]

I guess it be preferable to keep the current behavior as default, let me correct that commit.

[KoBeWi]

Implementation looks ok.

The feature is probably ok too. Shortcut feedback makes sense in apps, but not really in games I think. Maybe.

I'd rename the property though, because it's a bit awkward. It could be simply shortcut_feedback.

[akien-mga]

Thanks!