nextcloud-client: disable qml caching

There currently seems to be a chance that after a nextcloud-client
update it will crash on startup. This crashing can be fixed by deleting the
`~/.cache/Nextcloud/qmlcache` folder.

For the crashing behavior, see also:
* #127324
* #121594
* #119029
* ...

The workaround introduced in this commit is also already used by muse.
See: 842a0d94cb/pkgs/applications/audio/musescore/default.nix (L34)

pkgs/applications/networking/nextcloud-client/default.nix

@@ -60,6 +60,8 @@ mkDerivation rec {
 
   qtWrapperArgs = [
     "--prefix LD_LIBRARY_PATH : ${lib.makeLibraryPath [ libsecret ]}"
+    # See also: https://bugreports.qt.io/browse/QTBUG-85967
+    "--set QML_DISABLE_DISK_CACHE 1"
   ];
 
   cmakeFlags = [