Clear out status memory when an LSTAT message comes in

[rm5248]

This is at least a partial fix for #271. With this, the python code will no longer get a giant byte array for the report field when an LSTAT is requested:

OSDP: PD-0: 2025-12-22T22:50:09Z   osdp_pd.c:733  [DEBUG] CMD: LSTAT(64) REPLY: LSTATR(48)
PD: Received command: {'command': 9, 'type': 2, 'report': b''}

I'm not sure if the report field should be set in the first place, but least now it is a 0 byte length array.

[sidcha]

The event structure is an input to LibOSDP. When do_command_callback() is called, the PD app is expected to fill the event struct with the right data. See my comment on #271 for more details.