healthscope apply failed[BUG]

[xishengcai]

Describe the bug
healthscope can't pave， will report error: no fields

59s         Warning   CannotApplyComponents    applicationconfiguration/example-appconfig                          cannot find scope workloadRef "core.oam.dev/v1alpha2" "HealthScope" "example-health-scope" with workloadRefsPath "spec.workloadRefs": spec: no such field

if value, err := fieldpath.Pave(s.UnstructuredContent()).GetValue(workloadRefsPath); err == nil

To Reproduce

1. 定义healthscope

apiVersion: core.oam.dev/v1alpha2
kind: ScopeDefinition
metadata:
  name: healthscopes.core.oam.dev
spec:
  allowComponentOverlap: true
  workloadRefsPath: spec.workloadRefs
  definitionRef:
    name: healthscopes.core.oam.dev

2. 创建healthscope

apiVersion: core.oam.dev/v1alpha2
kind: HealthScope
metadata:
  name: example-health-scope

3. 应用scope

apiVersion: core.oam.dev/v1alpha2
kind: ApplicationConfiguration
metadata:
  name: example-appconfig
spec:
  components:
    - componentName: example-component
      parameterValues:
        - name: instance-name
          value: example-appconfig-workload1
        - name: image
          value: wordpress:php7.2
      traits:
        - trait:
            apiVersion: core.oam.dev/v1alpha2
            kind: ManualScalerTrait
            metadata:
              name: example-appconfig-trait
            spec:
              replicaCount: 2
      scopes:
        - scopeRef:
            apiVersion: core.oam.dev/v1alpha2
            kind: HealthScope
            name: example-health-scope

4. kubectl get event -w , you will find the Warning

[captainroy-hy]

Miss a required field when creating a HealthScope

apiVersion: core.oam.dev/v1alpha2
kind: HealthScope
metadata:
  name: example-health-scope
spec:
  workloadRefs: [] # <-- this field is required