a11y: Sanitize the AT-SPI object path further
When falling back to g_get_prgname(), we need to take into account that the program name may be the full argv[0] path, which will end up messing the DBus object path.
When falling back to g_get_prgname(), we need to take into account that the program name may be the full argv[0] path, which will end up messing the DBus object path.