Rename Yuni_(wordless)_(Nikke)

BUR #39864 has been approved by @nonamethanks.

rename yuni_(wordless)_(nikke) -> yuni_(chimera)_(nikke)

Yuni's new form was given an official name via Nikke's official Popularity Poll

The bulk update request #39864 (forum #346662) has been approved by @nonamethanks.