Revert "Revert "Migrate IDP_GRID_NAME usage to LauncherPrefs""

This reverts commit df119597.

Bug: 269569568
Test: In follow-up CL, everything works on device and manual and unit tests
verified original bug from this CL is not present.

Change-Id: I125bbbfd6442cd3fa1e88c9109de536b88981dc6