The properties editors are global but the frame that they reference is
not static, so we need to be able to update the frame reference when
restarting pcb editor from the main window. This updates the frame,
being careful to remove the signalling when closing pcbnew but keeping
the instance of the editor in place.
Fixes https://gitlab.com/kicad/code/kicad/issues/12297
Jon Evans
Alex
Seth Hillbrand