[favourites] only add return if the builtin is ActivateWindow

[enen92]

This was reported in the kodi core repo: https://github.com/xbmc/xbmc/issues/20648 While investigating it decided to fix it too - there's no reason to append return) to any builtin unless the builtin is ActivateWindow where the parameter actually takes any effect. @anxdpanic by the commit history I think you might have access to this repo right?

[anxdpanic]

Thanks @enen92 👍