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.

[main]
host = https://www.transifex.com

[beremiz-ide.beremiz]
file_filter = Beremiz_<lang>.po
minimum_perc = 0
source_file = messages.pot
source_lang = en
type = PO