QS: Remote Display: improved handling of media router callback
Our previous solution: media router callback was registered constantly
which under special circumstances could lead to the wake locks held by
remote display API.

Stock behaviour: registration/unregistration of callback together with
remote display state refresh happens on panel visibility change (using
onPrepareListener of QS tile) which also happens while user is expanding
panel which leads to hick-ups/glitches of status bar panels during
expansion.

New solution: media router callback gets registered and remote display
state is refreshed after QS panel gets fully opened and unregistered
when QS panel gets fully collapsed. This avoids keeping callback
registered all the time + avoids panel glitches at the same time.