Draft: port-probe: never ignore QCDM port

External programs like fwupd rely on ModemManager's port probing results to discover a Modem's ports. Currently only if MM_PLUGIN_REQUIRED_QCDM is set, the QCDM port will be probed. If the port is flagged as QCDM in the Udev rules and only MM_PLUGIN_ALLOWED_QCDM is set, the port will be set to ignored without probing and therefore not visible as QCDM via mm_modem_get_ports().

Set the port type to MM_PORT_TYPE_QCDM for both MM_PLUGIN_REQUIRED_QCDM and MM_PLUGIN_ALLOWED_QCDM if a QCDM port hint exists in the Udev rules.