fix(prefs_win): Remove unsupported properties
GtkFontChooserWidget had some properties which are not supported in all
versions of GTK+, and were causing crashes instead of gracefully adapting.
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="font"/>
- <property name="language">en-gb</property>
- <property name="level">GTK_FONT_CHOOSER_LEVEL_SIZE | GTK_FONT_CHOOSER_LEVEL_FAMILY</property>
</object>
<packing>
<property name="left_attach">1</property>
