As suggested in review, merge both HoverClickSounds constructors into
one accepting optional arguments. Due to existing usages the parameter
is added as second and supplied by name in ModButton.
As suggested in review, remove previously introduced HoverMouseUpSounds
and instead change effect playing logic in HoverClickSounds by moving it
out of OnClick() to OnMouseUp().
Users of the class can either use the existing constructor to play
the effect only on left click or use the newly introduced constructor
with the MouseButton[] parameter to specify which button clicks should
trigger the sound.
