Remove the NECROPET power target type

No power uses it after DRU-066 moved to the Powers.cfg Pet type, and its
area query (WorldGrid.getObjectsInRangePartialNecroPets) was an empty
stub. The DB rows are aligned with sql/necro-pet-targeting.sql.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/engine/InterestManagement/WorldGrid.java

@@ -118,11 +118,6 @@ public class WorldGrid {
         return outbound;
     }
 
-    public static HashSet<AbstractWorldObject> getObjectsInRangePartialNecroPets(Vector3fImmutable loc, double r) {
-        HashSet<AbstractWorldObject> outbound = new HashSet<>();
-        return outbound;
-    }
-
     public static HashSet<AbstractWorldObject> getObjectsInRangeContains(Vector3fImmutable loc, double r, int mask) {
         HashSet<AbstractWorldObject> outbound = getObjectsInRangePartial(loc, r, mask);
         return outbound;