malcontent: Reload the app filter when it changes

All the code to reload all the apps and re-filter them was in place and working, but I forgot to actually reload the filter when it changed, leading to re-filtering the apps using the old filter.

This fixes reloading apps when the user’s app filter is changed in the separate parental controls app (malcontent-control).

Signed-off-by: Philip Withnall withnall@endlessm.com