Add support for username and domain fields to ShellMountPasswordDialog
ShellMountPasswordDialog doesn't support
ANONYMOUS_SUPPORTED values of
AskPasswordFlags and thus it is not used for these cases when mounting something from GTK apps: https://gitlab.gnome.org/GNOME/gtk/-/blame/master/gtk/gtkmountoperation.c#L902-903. Consequently, the shell dialog is shown for e.g.
sftp://user@server/ and the GTK dialog for
sftp://server/ when mounting from Nautilus, or other GTK apps, which is ridiculous. Can support for these flags can be added?