Properly set accessibility labels for AdwCombo object-select-symbolic images
I was using the new Gtk Inspector's "show accessibility warnings" feature and the factory items inside an AdwCombo were showing missing labels for the "is this selected" image.
See https://gitlab.gnome.org/GNOME/libadwaita/-/blob/main/src/adw-combo-row.c?ref_type=heads#L274 (which adds an image of object-select-symbolic
) and related code that changes its opacity.