Only add tray widgets after the SNI proxy has finished initializing and the
item has a valid id/category pair.
This also removes invalid items through the host teardown path, refreshes the
tray when item status changes, and avoids calling DBus methods through a null
proxy during early clicks or scroll events.
Signed-off-by: Austin Horstman <khaneliman12@gmail.com>
2a748f1a56