Remove auth as required property in chat

[JohnHKoh]

Removing auth as a required property as chat messages may not have it in the body. I assume that null cases have already been handled elsewhere in the code because the schema already accepts "auth": null. Hopefully lol.

{
  "name":"Some Ball 1",
  "team":2,
  "from":1,
  "message":"im bad",
  "to":"team",
  "removeAt":1666981608117
}

Should address #296.