fix(room2d): Fix bug introduced when capping planar holes in rooms

dragonfly/room2d.py

@@ -4111,6 +4111,8 @@ def _cap_planar_holes(self, room_polyface, roof_face_i, tolerance):
         """
         # join all of the naked edges into closed loops
         naked_edges = room_polyface.naked_edges
+        if len(naked_edges) == 0:
+            return room_polyface, roof_face_i
         joined_loops = Polyline3D.join_segments(naked_edges, tolerance)
 
         # create Face3D from any closed planar loops