Description of problem:
 EgressIP was not balanced to another egress node after original node was removed egress label

Version-Release number of selected component (if applicable):
4.10.0-0.nightly-2022-03-29-163038

How reproducible:
Hard to reproduce in manual test, but frequently failing in auto case.

Steps to Reproduce:
$ oc get nodes
NAME                                        STATUS   ROLES    AGE    VERSION
ip-10-0-50-148.us-east-2.compute.internal   Ready    master   109m   v1.23.5+1f952b3
ip-10-0-54-82.us-east-2.compute.internal    Ready    master   109m   v1.23.5+1f952b3
ip-10-0-55-50.us-east-2.compute.internal    Ready    worker   91m    v1.23.5+1f952b3
ip-10-0-58-148.us-east-2.compute.internal   Ready    worker   91m    v1.23.5+1f952b3
ip-10-0-65-102.us-east-2.compute.internal   Ready    master   109m   v1.23.5+1f952b3
ip-10-0-65-115.us-east-2.compute.internal   Ready    worker   91m    v1.23.5+1f952b3

1. Label one node as egress node ip-10-0-55-50.us-east-2.compute.internal
2. Create namespace test and add label name=qe
3. Create egressip object, egressip was successfully assigned.

 oc get egressip
NAME             EGRESSIPS     ASSIGNED NODE                              ASSIGNED EGRESSIPS
egressip-47028   10.0.55.117   ip-10-0-55-50.us-east-2.compute.internal   10.0.55.117

oc get egressip -o yaml
apiVersion: v1
items:
- apiVersion: k8s.ovn.org/v1
  kind: EgressIP
  metadata:
    annotations:
      kubectl.kubernetes.io/last-applied-configuration: |
        {"apiVersion":"k8s.ovn.org/v1","kind":"EgressIP","metadata":{"annotations":{},"name":"egressip-47028"},"spec":{"egressIPs":["10.0.55.117","10.0.52.72"],"namespaceSelector":{"matchLabels":{"name":"test"}}}}
    creationTimestamp: "2022-03-31T02:40:33Z"
    generation: 2
    managedFields:
    - apiVersion: k8s.ovn.org/v1
      fieldsType: FieldsV1
      fieldsV1:
        f:status:
          .: {}
          f:items: {}
      manager: ip-10-0-50-148
      operation: Update
      time: "2022-03-31T02:40:33Z"
    - apiVersion: k8s.ovn.org/v1
      fieldsType: FieldsV1
      fieldsV1:
        f:metadata:
          f:annotations:
            .: {}
            f:kubectl.kubernetes.io/last-applied-configuration: {}
        f:spec:
          .: {}
          f:egressIPs: {}
          f:namespaceSelector:
            .: {}
            f:matchLabels:
              .: {}
              f:name: {}
      manager: kubectl-client-side-apply
      operation: Update
      time: "2022-03-31T02:40:33Z"
    name: egressip-47028
    resourceVersion: "47028"
    uid: 078d97d7-e6dd-43e7-9662-4174576bcfe2
  spec:
    egressIPs:
    - 10.0.55.117
    - 10.0.52.72
    namespaceSelector:
      matchLabels:
        name: test
  status:
    items:
    - egressIP: 10.0.55.117
      node: ip-10-0-55-50.us-east-2.compute.internal
kind: List
metadata:
  resourceVersion: ""
  selfLink: ""

Actual results:

4. Remove egress label from node ip-10-0-55-50.us-east-2.compute.internal
Add egress label to another node ip-10-0-58-148.us-east-2.compute.internal

oc get node ip-10-0-55-50.us-east-2.compute.internal --show-labels
NAME                                       STATUS   ROLES    AGE   VERSION           LABELS
ip-10-0-55-50.us-east-2.compute.internal   Ready    worker   51m   v1.23.5+1f952b3   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/instance-type=m5.xlarge,beta.kubernetes.io/os=linux,failure-domain.beta.kubernetes.io/region=us-east-2,failure-domain.beta.kubernetes.io/zone=us-east-2a,kubernetes.io/arch=amd64,kubernetes.io/hostname=ip-10-0-55-50.us-east-2.compute.internal,kubernetes.io/os=linux,node-role.kubernetes.io/worker=,node.kubernetes.io/instance-type=m5.xlarge,node.openshift.io/os_id=rhcos,topology.ebs.csi.aws.com/zone=us-east-2a,topology.kubernetes.io/region=us-east-2,topology.kubernetes.io/zone=us-east-2a

oc get node ip-10-0-58-148.us-east-2.compute.internal --show-labels
NAME                                        STATUS   ROLES    AGE   VERSION           LABELS
ip-10-0-58-148.us-east-2.compute.internal   Ready    worker   51m   v1.23.5+1f952b3   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/instance-type=m5.xlarge,beta.kubernetes.io/os=linux,failure-domain.beta.kubernetes.io/region=us-east-2,failure-domain.beta.kubernetes.io/zone=us-east-2a,k8s.ovn.org/egress-assignable=true,kubernetes.io/arch=amd64,kubernetes.io/hostname=ip-10-0-58-148.us-east-2.compute.internal,kubernetes.io/os=linux,node-role.kubernetes.io/worker=,node.kubernetes.io/instance-type=m5.xlarge,node.openshift.io/os_id=rhcos,topology.ebs.csi.aws.com/zone=us-east-2a,topology.kubernetes.io/region=us-east-2,topology.kubernetes.io/zone=us-east-2a

Actual Result:

5. Check egressip object, the assigned node was not updated
$ oc get egressip
NAME             EGRESSIPS     ASSIGNED NODE                              ASSIGNED EGRESSIPS
egressip-47028   10.0.55.117   ip-10-0-55-50.us-east-2.compute.internal   10.0.55.117

$ oc get CloudPrivateIPConfig
No resources found

Expected Result:
The assigned node should be updated correctly in egressip object.

Additional info: