Move QSPanelControllerBase callback to init/destroy

Before this change, attaching and dettaching QSFragment would trigger
tiles re-fetching and recreating of callbacks and views. In order to
prepare for scenes (where we may want to dettach and re-attach QSImpl),
this does the following two changes:

* The callback to QSHost is added in `init` and removed in `destroy`.
* If the tiles collection is exactly the same as the current one (same
  QSTile objects, in same order), do not re-create the TileRecord and
  views.

Bug: 280887232
Test: manual
Test: atest QSPanelControllerBaseTest
Test: heapdump, no leftover QSImpl after recreating QSFragmentLegacy
Change-Id: Ie27d23c34cbb4c8d645d6cd3df5d0812ab6ff70a