wxPython4 sequels: fix Wx exceptions ignored because no traceback

Some exception triggered on wxPython side have None as traceback,
and exception hanlder was discarding them.

<?xml version='1.0' encoding='utf-8'?>
<BeremizRoot URI_location="LOCAL://">
  <TargetType/>
  <Libraries Enable_SVGHMI_Library="true"/>
</BeremizRoot>