Exported texture atlases are different each time

The bug

When using F3+S to print dynamic texture atlases, the files will be different almost every time as the game doesn't account for animated textures properly.

How to reproduce

1. Use F3+S to create a debug folder in the screenshots directory
2. Rename this folder
3. Use F3+S again
4. Compare the versions of minecraft_textures_atlas_blocks.png_0 generated

Expected results

The files would be an exact match.

Actual results

There are major differences where the animated textures are.

How to fix

When printing the atlases, only use the first frame of each animated texture as to remove this nondeterminicity.