Appimage: Replace patch for KF6 kcmutils a symlink

* patches-appimage/kleopatra/0001-Make-KCMUtils-optional.patch:
Make it a symlink to the windows patch.

This patch does not really work for our KF5 branch but changing
the code back is also a bit effort so I kept the patch around
since we plan to switch to KF6 probably after the next release
anyway.