Some types of audit event samples from [our documentation](https://www.elastic.co/guide/en/elasticsearch/reference/7.17/audit-event-types.html) include the port number in "origin.address", like **access_denied**:
```json
{"type":"audit", "timestamp":"2020-12-30T22:30:06,949+0200", "node.id":
"0RMNyghkQYCc_gVd1G6tZQ", "event.type":"transport", "event.action":
"access_denied", "authentication.type":"REALM", "user.name":"user1",
"user.realm":"default_native", "user.roles":["test_role"], "origin.type":
"rest", "origin.address":"[::1]:52434", "request.id":"yKOgWn2CRQCKYgZRz3phJw",
"action":"indices:admin/auto_create", "request.name":"CreateIndexRequest",
"indices":["<index-{now/d+1d}>"]}
```
but other types like **connection_denied** from this issue does not include the port:

```json
{"type":"audit", "timestamp":"2020-12-30T21:47:31,526+0200", "node.id":
"0RMNyghkQYCc_gVd1G6tZQ", "event.type":"ip_filter", "event.action":
"connection_denied", "origin.type":"rest", "origin.address":"10.10.0.20",
"transport.profile":".http", "rule":"deny 10.10.0.0/16"}
```

I think we should be consistent here and always include the port number in the "origin.address" field.
x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/transport/filter/IPFilterTests.java
private IPFilter ipFilter;
    private MockLicenseState licenseState;
    private AuditTrail auditTrail;
    private AuditTrailService auditTrailService;
    private Transport transport;
    private HttpServerTransport httpTransport;
    private ClusterSettings clusterSettings;
    @Before
    public void init() {
        licenseState = TestUtils.newMockLicenceState();
        when(licenseState.isAllowed(Security.IP_FILTERING_FEATURE)).thenReturn(true);
        when(licenseState.isAllowed(Security.AUDITING_FEATURE)).thenReturn(true);
        auditTrail = mock(AuditTrail.class);
        auditTrailService = new AuditTrailService(Collections.singletonList(auditTrail), licenseState);
        clusterSettings = new ClusterSettings(