Removes an currently unused Enigma Sprite I added (#6759)

The animation is massive. I do not plan to finish Revenant anytime soon.
No cheap mental omega reference this time in PR description.

## About The Pull Request

Opinions on things shift quickly on what one should do with time.

## Why It's Good For The Game

Its a massive sprite that is currently unused. It has a rather long
animation. I do not plan to finish P4 Revenant. I rather not have this
massive unused sprite lying around (it is honestly quite large for a
single sprite, inital PR introducing all 3 show the three alone
increased filesize by 240% :') )

Why not finish it Irkalla? Well, I got my reasons to not finish it. If
_Evanne/Serin_ wants to use it ingame yeah I guess I can PR the thing
sometime. Same goes for other projects (Morphium Rifle, the funny IV
drip collapsable bed, shrapnell extractor for field shrap removal).

If somebody cares enough on the exact why my DMs are open.


## Changelog

:cl:
del: A single but still quite massive sprite.
/:cl: