Restore hotseat when user turns off suggestions immediately after migration

- Creates a backup table `hybrid_hotseat_restore` and copies current workspace layout before hotseat migration
- restores to back up when user turns off suggestions and launcher receives empty predicted items
- deletes hybrid_hotseat_restore table if there's a layout change

Test: Manual
Bug: 157688471
Change-Id: Iaf7ddb33799493d36dbcd12408b57224162221d9