text: Title: Endpoint slice mirroring controller mirrors kubectl  kubectl.kubernetes.io/last-applied-configuration
  Body: #### What happened:
  
  If I modify a custom endpoint, the kubectl kubectl.kubernetes.io/last-applied-configuration annotation is mirrored to the generated endpoint slice
  
  #### What you expected to happen:
  
  Since the kubect last-applied-configuration tracks the status of the object, it shouldn't be mirrored since it doesn't apply to the generated object
  
  #### How to reproduce it (as minimally and precisely as possible):
  
  1. Create a custom endpoint
  1. Apply an update on any of the fields
  1. Check the generated endpoint slice annotations
  
  ```yaml
  kubectl get endpointslices ep-test-ljgn7 -o yaml                                                                                                                                                    
  addressType: IPv4                                                                                                                                                                                                     
  apiVersion: discovery.k8s.io/v1                                                                                                                                                                                       
  endpoints:                                                                                                                                                                                                            
  - addresses:                                                                                                                                                                                                          
    - 193.99.144.80                                                                                                                                                                                                     
    conditions:                                                                                                                                                                                                         
      ready: true                                                                                                                                                                                                       
  - addresses:                                                                                                                                                                                                          
    - 195.54.164.39
    conditions:
      ready: true
  kind: EndpointSlice
  metadata:
    annotations:
      kubectl.kubernetes.io/last-applied-configuration: |
        {"apiVersion":"v1","kind":"Endpoints","metadata":{"annotations":{},"name":"ep-test","namespace":"default"},"subsets":[{"addresses":[{"ip":"193.99.144.80"}],"notReadyAddresses":[{"ip":"195.54.164.39"}],"ports":[{"name":"http","port":80,"protocol":"TCP"},{"name":"https","port":443,"protocol":"TCP"}]}]}
    creationTimestamp: "2021-06-08T07:35:24Z"
    generateName: ep-test-
    generation: 1
    labels:
      endpointslice.kubernetes.io/managed-by: endpointslicemirroring-controller.k8s.io
      kubernetes.io/service-name: ep-test
    managedFields:
    - apiVersion: discovery.k8s.io/v1
      fieldsType: FieldsV1
      fieldsV1:
        f:addressType: {}
        f:endpoints: {}
        f:metadata:
          f:annotations:
            .: {}
            f:kubectl.kubernetes.io/last-applied-configuration: {}
          f:generateName: {}
          f:labels:
            .: {}
            f:endpointslice.kubernetes.io/managed-by: {}
            f:kubernetes.io/service-name: {}
          f:ownerReferences:
            .: {}
            k:{"uid":"21dc11be-4794-4db8-93c2-8c9fb208e75e"}: {}
        f:ports: {}
      manager: kube-controller-manager
      operation: Update
      time: "2021-06-08T07:35:24Z"
    name: ep-test-ljgn7
  
  ```
  
  /sig network
  