Add grid scope to SpannegGrids

This enables us to:
- Provide the item span via a modifier
- Receive the row/column of each item similar to how LazyGridState provides a list of LazyGridItemInfos

Flag: com.android.systemui.qs_ui_refactor_compose_fragment
Test: screenshot tests
Fixes: 379309901

Change-Id: I4af0063d8570bb572b4df07213c61e53fd6d4ac3