Appmenu quite neatly has a config option for which should be the
preferred representation, which is needed as both things are quite
viable in a panel and can't be done automatically.

AppletQuickItem needs to update which representation to use when this is
set at runtime. We already check on every single geometry change, so
one extra check won't have a huge impact.

Appmenu changes dynamically
All other applets (both compact and normal) still seem fine