arknights: endfield qualifer rename

BUR #23949 has been rejected.

rename perlica_(arknights) -> perlica_(arknights:_endfield)
rename ember_(arknights) -> ember_(arknights:_endfield)
rename chen_qianyu_(arknights) -> chen_qianyu_(arknights:_endfield)

Although arknights:_endfield is sequel of arknights I think their own characters should have more specific qualifier.

Maybe just "endfield"?

If its in the future and past characters are assumingely dead, is this even necessary?

This bulk update request is pending automatic rejection in 5 days.

This bulk update request has been rejected because it was not approved within 45 days.

The bulk update request #23949 (forum #271334) has been rejected by @DanbooruBot.