Only check dbFile to decide if grid migration is needed

Fix: 234847755
Test: With a modified local build, when changing display config to swap between same grid:
- When dbFile is same but device type is different, no migration is performed
- When both dbFile and device type are different, migration is performed properly
Test: Grid migration through Wallpaper & Styles still works properly

Change-Id: Ie7429a7d59c135ba47061cae21c40b8d8af7188a

src/com/android/launcher3/model/DeviceGridState.java

@@ -134,10 +134,13 @@ public class DeviceGridState implements Comparable<DeviceGridState> {
      * DeviceGridState without migration, or false otherwise.
      */
     public boolean isCompatible(DeviceGridState other) {
-        if (this == other) return true;
-        if (other == null) return false;
-        return mNumHotseat == other.mNumHotseat
-                && Objects.equals(mGridSizeString, other.mGridSizeString);
+        if (this == other) {
+            return true;
+        }
+        if (other == null) {
+            return false;
+        }
+        return Objects.equals(mDbFile, other.mDbFile);
     }
 
     public Integer getColumns() {