test_rebuild uses non-existing method rebuild() for BHoMBaseWindow #257

Approving as it works as advertised, Though when running the tests, the test_rebuild test fails. I have looked at the blame for it and I think it was mistakenly added a while ago but ignored as tkinter tests tend to break by virtue of using tkinter (see heatmap tests breaks because of tk.tcl occasionally)

(I point it out as there is no such method rebuild on BHoMBaseWindow or its base classes)

Originally posted by @Tom-Kingstone in #256 (review)

I assume the method itself was removed at some point in the past.