Handle UnicodeDecodeErrors in window name
Handle UnicodeDecodeErrors in window name

Currently, a UnicodeDecodeError is unhandled meaning a `Window` object
is not created where this error arises.

This PR adds handling for the error by providing a fallback in the
`_property_utf8` method.

Fixes #3161

qtile/qtile,ramnes/qtile,ramnes/qtile,qtile/qtile