`self`Action in ACNP is not working well, need update to `Self`

[Jexf]

Describe the bug

Add an ACNP, as example:

apiVersion: crd.antrea.io/v1alpha1
kind: ClusterNetworkPolicy
metadata:
  name: default-ns-isolation
spec:
  priority: 2
  tier: baseline
  appliedTo:
    - namespaceSelector: {}       # Selects all Namespaces in the cluster
  ingress:
    - action: Allow
      from:
        - namespaces:
            match: self           # Allow from Pods from same Namespace
      name: AllowFromSameNS
      enableLogging: false
    - action: Drop
      from:
        - namespaceSelector: {}   # Drop from Pods from other all Namespaces
      name: DropFromAllOtherNS
      enableLogging: true
  egress:
    - action: Allow
      to:
        - namespaces:
            match: self           # Allow to Pods from same Namespace
      name: AllowToSameNS
      enableLogging: false
    - action: Drop
      to:
        - namespaceSelector: {}   # Drop to Pods from all other Namespaces
      name: DropToAllOtherNS
      enableLogging: true

But the pods in the same namespace also can not to ping each other.

[root@node-04 ~]# kubectl  get po -A -owide |grep test
test-1   test-app-1-6bdx5                1/1     Running   6          55d    10.224.1.5       tos-06   <none>           <none>
test-1   test-app-1-brmzs                1/1     Running   6          55d    10.224.0.5       tos-04   <none>           <none>
test-1   test-app-1-zrcgr                  1/1     Running   6          55d    10.224.2.10     tos-05   <none>           <none>

[root@node-04 ~]# kubectl  exec -ti -n test-1 test-app-1-brmzs -- ping 10.224.1.5
PING 10.224.1.5 (10.224.1.5) 56(84) bytes of data.
^C
--- 10.224.1.5 ping statistics ---
925 packets transmitted, 0 received, 100% packet loss, time 1120ms

The current supported NamespaceMatchType is Self. so follow the configuration in the guide document https://antrea.io/docs/v1.4.0/docs/antrea-network-policy/ will not work well.

// NamespaceMatchType describes Namespace matching strategy.
type NamespaceMatchType string

const (
	NamespaceMatchSelf NamespaceMatchType = "Self"
)

Versions:
Antrea 1.4.0