Fixes issues with block sound volume introduced in 1.21.5.
Grass block sounds have been reverted to their pre-1.21.5 versions and reduced by 4dB. They're quieter than before, but louder than in vanilla 1.21.5.
Cactus flower sounds have been reduced by 6dB. I found the sound very grating.
I might add more changes as I keep playing. Normally Mojang is very good at sound mixing, so there might not be anything else I want to change.
