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/main/java/org/elasticsearch/xpack/security/audit/logfile/LoggingAuditTrail.java
private static final Logger LOGGER = LogManager.getLogger(LoggingAuditTrail.class);
    public static final String REST_ORIGIN_FIELD_VALUE = "rest";
    public static final String LOCAL_ORIGIN_FIELD_VALUE = "local_node";
    public static final String TRANSPORT_ORIGIN_FIELD_VALUE = "transport";
    public static final String IP_FILTER_ORIGIN_FIELD_VALUE = "ip_filter";
    public static final String SECURITY_CHANGE_ORIGIN_FIELD_VALUE = "security_config_change";
    
    public static final String LOG_TYPE = "type";
    public static final String TIMESTAMP = "timestamp";
    public static final String ORIGIN_TYPE_FIELD_NAME = "origin.type";
    public static final String ORIGIN_ADDRESS_FIELD_NAME = "origin.address";
    public static final String NODE_NAME_FIELD_NAME = "node.name";
    public static final String NODE_ID_FIELD_NAME = "node.id";
    public static final String HOST_ADDRESS_FIELD_NAME = "host.ip";
    public static final String HOST_NAME_FIELD_NAME = "host.name";
    public static final String CLUSTER_NAME_FIELD_NAME = "cluster.name";
    public static final String CLUSTER_UUID_FIELD_NAME = "cluster.uuid";
    public static final String EVENT_TYPE_FIELD_NAME = "event.type";
    public static final String EVENT_ACTION_FIELD_NAME = "event.action";
    public static final String PRINCIPAL_FIELD_NAME = "user.name";
    public static final String PRINCIPAL_RUN_BY_FIELD_NAME = "user.run_by.name";
    public static final String PRINCIPAL_RUN_AS_FIELD_NAME = "user.run_as.name";