Does not notice when a modem goes away
when toggling of the kill switch the modem stays visible in
$ mmcli -L /org/freedesktop/ModemManager1/Modem/1 [manufacturer unknown] model unknown
when doing a
mmcli -r -m 0 it correctly vanishes. I don't think MM has a way to correctly notice this except for polling (and we certainly don't want it to wake up a suspended modem) so i'm not yet sure what's the best thing to do here.