StatefulSet IP preallocation cannot work as expected

[gran-vmv]

Describe the bug
FlexibleIPAM e2e cases always failed

    --- FAIL: TestAntreaIPAM/testAntreaIPAMStatefulSetDedicated (18.02s)
    --- FAIL: TestAntreaIPAM/testAntreaIPAMStatefulSetShared (18.02s)

The StatefulSet Pods cannot use reserved IPs.

=== RUN   TestAntreaIPAM/testAntreaIPAMStatefulSetDedicated
    antreaipam_test.go:553: expectedIPAddressMap: {"192.168.240.130":{"ipAddress":"192.168.240.130","phase":"Allocated","owner":{"pod":{"name":"sts-test-atii00wt-0","namespace":"antrea-ipam-test","containerID":""},"statefulSet":{"name":"sts-test-atii00wt","namespace":"antrea-ipam-test","index":0}}},"192.168.240.131":{"ipAddress":"192.168.240.131","phase":"Allocated","owner":{"pod":{"name":"sts-test-atii00wt-1","namespace":"antrea-ipam-test","containerID":""},"statefulSet":{"name":"sts-test-atii00wt","namespace":"antrea-ipam-test","index":1}}}}
    antreaipam_test.go:584: IPPool status isn't correct: [{"ipAddress":"192.168.240.130","phase":"Reserved","owner":{"statefulSet":{"name":"sts-test-atii00wt","namespace":"antrea-ipam-test","index":0}}},{"ipAddress":"192.168.240.131","phase":"Reserved","owner":{"statefulSet":{"name":"sts-test-atii00wt","namespace":"antrea-ipam-test","index":1}}},{"ipAddress":"192.168.240.132","phase":"Allocated","owner":{"pod":{"name":"sts-test-atii00wt-0","namespace":"antrea-ipam-test","containerID":"28c3252057a5263e6da733d0818dea07e288fa971954ff3b49077c3f45d686d9"}}},{"ipAddress":"192.168.240.133","phase":"Allocated","owner":{"pod":{"name":"sts-test-atii00wt-1","namespace":"antrea-ipam-test","containerID":"601f5fdbc75710711e9330266a07aaca9c83b858cc3424c23d0bbcc5824352ef"}}}]

To Reproduce
Run FlexibleIPAM e2e with PR #6317

Expected
Pass all e2e cases.

Actual behavior
2 cases failed.

Versions:
main branch after PR #6317 merged

cc @luolanzone