fix: add additional properties in crd for metrics obj

[yashmehrotra]

apiVersion: canaries.flanksource.com/v1
kind: Canary
metadata:
  name: domain
spec:
  schedule: "@every 1m"
  http:
    - name: myDomain
      url: https://mydomain.com/
      thresholdMillis: 20000
      responseCodes: [201, 200, 301]
      metrics:
        - name: canary_checker_custom_http_status
          type: gauge
          value: "1"
          labels:
            - name: check_name
              valueExpr: check.name
            - name: url
              valueExpr: check.url

Was giving this error (Reported on Slack)

Error from server (BadRequest): error when creating "myDomain.yaml": Canary in version "v1" cannot be handled as a Canary: strict decoding error: unknown field "spec.http[0].metrics[0].labels", unknown field "spec.http[0].metrics[0].name", unknown field "spec.http[0].metrics[0].type", unknown field "spec.http[0].metrics[0].value"