Add multi-instance state to item infos

- Add legacy resource for supported multi-instance apps that
  matches the current SystemUI resource of the same name, and will
  be removed as apps migrate to the V manifest property to declare
  multi-instance support
- Load the multi-instance state from PackageManager when the db is
  first loaded or when packages are updated
- The multi-instance check is then used to determine if an app pair
  can be saved (ie. whether the action can be shown)

Bug: 323112914
Test: atest NexusLauncherTests

Merged-In: I565b4bee4ab5f7040910306b1fd60a4fc3bf9a1c
Change-Id: I9658b63672b692c42563c111c11be2433c98d535