[Bug] Wrong projection generated when `endpointCA` is not specified.

[mnencia]

When you do not specify an endpointCA, the resulting patch contains this operation:

  {
    "op": "add",
    "path": "/spec/volumes/4",
    "value": {
      "name": "barman-certificates",
      "projected": {
        "sources": null
      }
    }
  },

This is an invalid projection and could be rejected in some environments.