Unused pixels in parrot_[blue/green/red_blue/yellow_blue].png UV texture maps

There are unused pixels in 3 of the 5 UV texture maps for parrots, seemingly left over from when a palette was created for the different textures. For clarification, this is not reporting the white background, as that issue is MC-260786. This report is specifically to clarify that there are non-white pixels which go unused, and should be removed along side the white.

Unused:

(Unused pixels are highlighted in purple)
Blue:

Green:

Red_Blue:

Yellow_Blue:

Fixes:

This fix accounts for MC-260786, and should be resolved directly alongside it