No way to change device state json doc capacity

[tedbyron]

It looks like MQTT_MAX_PACKET_SIZE is being used as the MQTT client buffer size but not the state JSON doc size, why is that? Because the document size is so limited, when device state is too large it will just serialize to null. Increasing MQTT_MAX_PACKET_SIZE doesn't fix this as stated in the readme, because it doesn't change the doc size

[InconceivableDuck]

Hey @tedbyron! I believe this is an unexpected behavior change when we migrated from ArduinoJson v5 to v6. Whereas before this size only need to be large enough to include the wrapper, it appears as though it now may be copying the incoming state instead of supporting the pointer. Good catch!