Empty arrays properties sent as `null` upon reconnection. about astarte

[Annopaolo]

This is due to Scylla/Cassandra:

Note that Scylla does not distinguish an empty list from a missing value, thus assigning an empty list ([]) to a list is the same as deleting it.

(source: https://opensource.docs.scylladb.com/stable/cql/types.html)

The same behaviour also appears on datastreams:

❯curl -X POST -H "Accept: application/json" -H "Content-Type: application/json" \
        -H "Authorization: Bearer $TOKEN" \
        "http://api.astarte.localhost/appengine/v1/test/devices/$DEVICE/interfaces/$INTERFACE/array_endpoint" \
        --data '{"data" :[]}'
{"data":[]}                                                                                                                                                  
❯curl -X GET -H "Accept: application/json" -H "Content-Type: application/json" \
        -H "Authorization: Bearer $TOKEN" \
        "http://api.astarte.localhost/appengine/v1/test/devices/$DEVICE/interfaces/$INTERFACE"
{"data":{"array_endpoint":{"reception_timestamp":"2024-04-08T16:06:49.116Z","value":null}}}