games/anki: Update to 26.08

• Switch to USES=npm and adjust/remove the relevant parts.
  
  Although Yarn v4 is already being used according to "package.json", stick with Yarn v1 for now to complete a 1:1 migration from the before to the after state with respect to the used tools during build.

Changelog:

https://github.com/ankitects/anki/releases/tag/26.08