Added functions to pass launcher widget span info to preview

To calculate the widget scales correctly for the launcher preview in different grids, the span info of the widgets in the launcher is necessary. Querying the launcher widget info in the database and passing it to the preview render.

Test: Verified that no exceptions were happening when changing preview grid layouts
Bug: 228328759
Change-Id: I681d21b176c8fe5208431a79009d9ba8279cda6a