MbimSmsStatusFlag is not an enum it's flags

As per the MBIM 1.0 reference, the MBIM_SMS_STATUS_FLAGS is

a bitmap that represents possible status for the SMS message store.

And therefore:

NONE = 0,
MESSAGE_STORE_FULL = 1 << 0,
NEW_MESSAGE = 1 << 1,

So a value of '3' should be MESSAGE_STORE_FULL | NEW_MESSAGE, as seen here:

2022-12-05T12:27:52.720225Z DEBUG ModemManager[3315]: <debug> [/dev/cdc-wdm0] received message...
>>>>>> RAW:
>>>>>>   length = 52
>>>>>>   data   = 07:00:00:80:34:00:00:00:00:00:00:00:01:00:00:00:00:00:00:00:53:3F:BE:EB:14:FE:44:67:9F:90:33:A2:23:E5:6C:3F:05:00:00:00:08:00:00:00:03:00:00:00:01:00:00:00

2022-12-05T12:27:52.720480Z DEBUG ModemManager[3315]: <debug> [/dev/cdc-wdm0] received message (translated)...
>>>>>> Header:
>>>>>>   length      = 52
>>>>>>   type        = indicate-status (0x80000007)
>>>>>>   transaction = 0
>>>>>> Fragment header:
>>>>>>   total   = 1
>>>>>>   current = 0
>>>>>> Contents:
>>>>>>   service = 'sms' (533fbeeb-14fe-4467-9f90-33a223e56c3f)
>>>>>>   cid     = 'message-store-status' (0x00000005)
>>>>>> Fields:
>>>>>>   Flag = '(null)'
>>>>>>   MessageIndex = '1'

2022-12-05T12:27:52.720716Z DEBUG ModemManager[3315]: <debug> [modem1] received notification (service 'sms', command 'message-store-status')
2022-12-05T12:27:52.720802Z DEBUG ModemManager[3315]: <debug> [modem1] received SMS store status update: '(null)'