games/anki: Update to 2.1.46

* Remove DIST_SUBDIR, which once made sense when Anki was still a pure
  Python port.  Anki now needs a lot of Rust crates that are also used
  by other ports.

  Therefore, these crates should be placed in the usual place and not
  in an additional subdirectory to save bandwidth and disk space. [1]

Reported by:	se [1]
MFH:		2021Q3