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
for (TransportAddress address : transport.boundAddress().boundAddresses()) {
            addressStrings.add(NetworkAddress.format(address.address().getAddress()));
        }
        Settings settings;
        if (randomBoolean()) {
            settings = Settings.builder()
                .putList("xpack.security.transport.filter.deny", addressStrings.toArray(new String[addressStrings.size()]))
                .build();
        } else {
            settings = Settings.builder().put("xpack.security.transport.filter.deny", "_all").build();
        }
        ipFilter = new IPFilter(settings, auditTrailService, clusterSettings, licenseState);
        ipFilter.setBoundTransportAddress(transport.boundAddress(), transport.profileBoundAddresses());
        ipFilter.setBoundHttpTransportAddress(httpTransport.boundAddress());
        for (String addressString : addressStrings) {
            assertAddressIsAllowedForProfile(IPFilter.HTTP_PROFILE_NAME, addressString);
            assertAddressIsAllowedForProfile("default", addressString);
        }
    }
    public void testThatAllAddressesAreAllowedWhenLicenseDisablesSecurity() {
        Settings settings = Settings.builder().put("xpack.security.transport.filter.deny", "_all").build();
        when(licenseState.isAllowed(Security.IP_FILTERING_FEATURE)).thenReturn(false);
        ipFilter = new IPFilter(settings, auditTrailService, clusterSettings, licenseState);
        ipFilter.setBoundTransportAddress(transport.boundAddress(), transport.profileBoundAddresses());
        
        String message = String.format(Locale.ROOT, "Expected address %s to be allowed", "8.8.8.8");
        InetAddress address = InetAddresses.forString("8.8.8.8");
        assertThat(message, ipFilter.accept("default", new InetSocketAddress(address, 0)), is(true));
        verifyNoMoreInteractions(auditTrail);