graphics/darktable: unbreak AVIF=on after 3036600b61bd

> Checking for pkg-plist issues (check-plist)

> Parsing plist

> Checking for items in STAGEDIR missing from pkg-plist

Error: Orphaned: lib/darktable/plugins/imageio/format/libavif.so

> Checking for items in pkg-plist which are not in STAGEDIR

Error: Missing: %%LIBAVIF%%lib/darktable/plugins/imageio/format/libavif.so

> Error: Plist issues found.

• Error code 1

Pointy hat to: jbeich