PC3/BusyIndicator: Disable hover, drop unused id, and shorten a comment
IMHO what PC2 did or did not do about padding has little historical value for the modern code base of PC3 and qqc2-desktop-style implementations.
This is a sync back to frameworks/qqc2-desktop-style!197 (merged) which is a sync to PC3 with this much more stuff in it.