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/audit/logfile/LoggingAuditTrailFilterTests.java
private <T> List<T> randomListFromLengthBetween(List<T> l, int min, int max) {
        assert (min >= 0) && (min <= max) && (max <= l.size());
        final int len = randomIntBetween(min, max);
        final List<T> ans = new ArrayList<>(len);
        while (ans.size() < len) {
            ans.add(randomFrom(l));
        }
        return ans;
    }
    private static Authentication createSystemUserAuthentication(boolean isFallback) {
        if (isFallback) {
            return Authentication.newInternalFallbackAuthentication(SystemUser.INSTANCE, randomAlphaOfLengthBetween(3, 8));
        } else {
            return Authentication.newInternalAuthentication(SystemUser.INSTANCE, Version.CURRENT, randomAlphaOfLengthBetween(3, 8));
        }
    }
    private static Authentication createAuthentication(User user, String effectiveRealmName) {
        return createAuthentication(user, null, effectiveRealmName);
    }
    private static Authentication createAuthentication(User effectiveUser, @Nullable User authenticatingUser, String effectiveRealmName) {
        assert false == User.isInternal(effectiveUser);
        if (authenticatingUser != null) {
            return AuthenticationTestHelper.builder()
                .user(authenticatingUser)
                .realmRef(new RealmRef(UNFILTER_MARKER + randomAlphaOfLength(4), "test", "foo"))
                .runAs()
                .user(effectiveUser)
                .realmRef(new RealmRef(effectiveRealmName, "up", "by"))
                .build();
        } else {