End gateway beam movement animation is hardcoded

Relates to: MC-276497 MC-277503 MC-277519 MC-278361 MC-278362 MC-278363

The bug

The texture of the end gateway beam translates upwards with time. However, unlike most texture animations in the game, this does not use a .mcmeta file to define this animation, implying that the animation is hardcoded and cannot be changed.

How to fix

Introduce a .mcmeta file for the end gateway beam like what exists for all other animated textures in the game.