Fix the part-name test for the new head_proto part

tools/tests/test_npc_parts.py

@@ -11,7 +11,7 @@ class CliTests(unittest.TestCase):
     def test_part_names_are_known(self):
         self.assertEqual(
             set(npc_parts.PART_NAMES),
-            {"head", "face", "hand_l", "hand_r"},
+            {"head", "face", "hand_l", "hand_r", "head_proto"},
         )
 
     def test_blender_commands_fail_cleanly_without_bpy(self):