vteapp: Only install argb visual when required by options
vteapp: Only install argb visual when required by options

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