emulation: Allow unsetting the current-{directory,file}-uri
emulation: Allow unsetting the current-{directory,file}-uri

By passing "" (or an invalid, non-URI value), unset the property.

pjm0616/vte,thestinger/vte-ng,flaxandteal/gasket-vte,saitoha/vte-sixel,rvu95/vte,rvu95/vte,flaxandteal/gasket-vte,jessevdk/vte,rvu95/vte,rvu95/vte,jessevdk/vte,saitoha/vte-sixel,flaxandteal/gasket-vte,asivokon/vte-fx,thestinger/vte-ng,flaxandteal/gasket-vte,thestinger/vte-ng,jessevdk/vte,asivokon/vte-fx,pjm0616/vte,saitoha/vte-sixel,jessevdk/vte,asivokon/vte-fx,asivokon/vte-fx,pjm0616/vte