Rework Ghast Disc drop to be in line with other music disc drops

While a neat reward, the Ghast Music Disc dropping every time a player kills a ghast with their own fireball is excessive and thematically inconsistent with other music discs. Not only does this devalue the treasure-like nature of other music discs, it will also become a nuisance to find so many duplicate ghast discs due to the ease of obtaining the new disc.

It should be remembered that reflecting a ghast fireball is a primary method of defeating a ghast - in fact, nearly the only way if the player does not have a ranged weapon. Ghasts dropping the music disc when killed by a fireball is like skeletons dropping a music disc when killed with an arrow! Clearly, this devalues the music disc and clutters the world with excessive unstackable mob drops.

Similar to other music discs, I propose the ghast disc should only drop if the ghast is killed by a skeleton's arrow. This is thematically consistent with creepers dropping discs, and makes obtaining the disc a much more unique experience. Can you wrangle a skeleton from the soul sand valleys, or should you doom a ghast to an Uneasy Alliance in the Overworld? This change would improve the rewarding feeling for obtaining a disc, reduce mob drop clutter, and be more thematically consistent with other music disc mechanics. For these reasons, I believe the change should be made! Thank you.