Is your feature request related to a problem? Please describe.
The effect of consuming items to unlock a slot is currently very limited, consisting of items being consumed without a sound.

Describe the solution you'd like
A sound event that gets played when unlocking a slot through items. Probably best to have it only play for the player that made the action. The sound event could play some vanilla sound.

Describe alternatives you've considered
Using an existing sound event from vanilla. However doing so would limit the ability of overriding the specific sound effect with a resource pack.