Convert to icon provider and separate from TileUiState

This change allows to do two things in the state for compose tiles:

* Have a way to represent whether an icon is a constant or is given by a
  supplier.
* Separate it from the TileUiState so the whole tile is not recomposed
  if the icon supplier changes. This is sometimes the case with
  CustomTiles

Test: manual, perfetto observe no recomposition in sharing tile
Test: atest TileUiStateTest TileRequestDialogViewModelTest
Test: atest IconProviderTest
Bug: 389985793
Flag: com.android.systemui.qs_ui_refactor_compose_fragment

Change-Id: Iff8add85a1778c5b159585cb8028bee4065eab74