Bounding box should not accept 5 elements.

In the Model 2D, if the bounding box contains 5 coordinates, an exception is not raised while it should be.
https://github.com/pyansys/pyaedt/blob/42cd90e24cf3876f7c7f6818156d51559602276d/pyaedt/modeler/Model2D.py#L159