Support no animation during forme changes

[HisuianZoroark]

Was requested for smogon/pokemon-showdown#10166

Probably not the best way to do it but it certainly works.

[KrisXV]

I think this works for now, but I will probably aim for a way to unhardcode eventually

[alphazeba]

I'd worked on a similar idea to handle dynamax animations.
#2217

However, if there is a need for providing animation override flags, you could consider using an "override enum" as an optional input. You could use "none" or something, i could update to use "dynamax" and it could also be extended in the future for other universal overrides without adding more flags.