Refine health diagnosis output

[captainroy-hy]

• Refine the output of HealthScope when target workload has peer versioning workloads. The diagnosis will sort by the revision number in descending order. And if the revision order is larger than 3 and its required replicas is 0, don't show its diagnosis info.

  status:
  healthConditions:
  - componentName: example-component
  diagnosis: 'example-component-v6:Ready:1/1  example-component-v5:Ready:1/1  example-component-v4:Ready:0/0 '
  healthStatus: HEALTHY
  targetWorkload:
    apiVersion: core.oam.dev/v1alpha2
    kind: ContainerizedWorkload
    name: example-component-v6
    uid: 4242f59b-0cb9-4cd9-8641-fd128d59cd5a

• change HealthScope work interval from 1min => 10sec
• fix unstable unit test