Grass block side texture has functionally unused pixels

Relates to: MC-176095 MC-199660 MC-208679 MC-250985

May also relate to: MC-159560

The bug

The texture file grass_block_side.png contains several pixels which are completely impossible to see under normal circumstances. While their influence on gameplay is currently nothing more than how they affect mipmapping, their existence may pose a problem in future as is detailed in MC-265667, and it may be advisable to remove these pixels to avert this.

How to fix

Remove all of the green pixels from grass_block_side.png. A fixed version of the file is attached, which removes these pixels. Removing these pixels would also fix MC-262954.