Fix exception when sending group requests

[puddly]

Group requests don't work when downgrading to 2022.9.7 so this change is entirely to prevent an error from being thrown:

2022-10-10 12:24:45.058 DEBUG (MainThread) [zigpy_zigate.zigbee.application] Sending packet ZigbeePacket(src=None, src_ep=1, dst=AddrModeAddress(addr_mode=<AddrMode.Group: 1>, address=0x0002), dst_ep=None, source_route=None, extended_timeout=False, tsn=37, profile_id=260, cluster_id=6, data=Serialized[b'\x01%\x00'], tx_options=<TransmitOptions.NONE: 0>, radius=0, non_member_radius=3, lqi=None, rssi=None)
2022-10-10 12:24:45.058 DEBUG (MainThread) [zigpy_zigate.api] Sending CommandId.SEND_RAW_APS_DATA_PACKET (b'\x01\x00\x02\x01\x00\x00\x06\x01\x04\x00\x00\x03\x01%\x00'), waiting for status: True, waiting for response: None
2022-10-10 12:24:45.058 DEBUG (MainThread) [zigpy_zigate.api] Wait for status to command CommandId.SEND_RAW_APS_DATA_PACKET
2022-10-10 12:24:45.094 DEBUG (MainThread) [zigpy_zigate.api] Response received: ResponseId.STATUS [<Status.Success: 0>, 0, 1328, b'\x01\xea\x00\x00'] 0 (LQI:b'')

Sniffer shows no traffic leaving ZiGate.

@doudz Are multicast/group requests expected to work?

[pipiche38]

@puddly, my understanding is that group and multicast required an firmware upgrade. But unfortunately the zigate project seems to be dead.
No bug fixes, no firmware update since ages

fairecasoimeme/ZiGate#385
fairecasoimeme/ZiGate#384

[doudz]

@pipiche38 : ZiGate project is not dead at all, last firmware was released on last december and Fairecasoimeme is working hard on hardware stuff

@puddly : Group request is not working yet with zigpy because of missing feature in the firmware, as pipiche38 said