Charged creeper power animation is hardcoded

Relates to: MC-276497 MC-277503 MC-277519

The bug

The animation used for charged creepers does not use an associated .mcmeta file, unlike almost all other animated textures in the game, including animated entity textures such as conduits.

How to fix

Introduce a .mcmeta file for charged creepers like what exists for all other animated textures in the game.