Unable to pass "null" values to custom cypher procedures

[lewisparma]

After upgrading from 2.16.3 version to 2.19.2 we are no longer able to send null values to custom neo4j procedures.

Here are the params received through the graphql mutation:

{
  "name": "asd8",
  "settings": {
    serialNumber: '123456',
    ip: '10.0.0.1',
    **binding: null,**
    labels: [],
  }
}

And here is what neo4j-graphql-js sends downs:

CALL apoc.cypher.doIt("CALL custom.inventory.device.create($name, $settings.serialNumber,  $settings.ip, $settings.labels, $settings.binding) YIELD node RETURN node",...........
{
  "name": "asd8",
  "settings": {
    "serialNumber": "123456",
    "ip": "10.0.0.1",
    **"binding": {},**
    "labels": [],
  },
  "first": -1,
  "offset": 0,
}

As you can see null values are passed down as an empty map. We do not use auto generated mutations, they are manually defined and they just call the "neo4jgraphql" function.

[michaeldgraham]

#608