MDEV-37060: Don’t check Encrpyted Server IDs in mariadb-binlog

MSAN found that `mariadb-binlog --force-read` checks encrypted events
too for whether `--do-server-ids`/`ignore-server-ids` includes any of
their (uninitialized) Server IDs.
This fix extends the condition to stop skipping `UNKNOWN_EVENT`s by
Server ID in addition to `ROTATE_EVENT`s.

An alternative solution is to zero-initialize the `server_id` field of
`Unknown_log_event` or even its supertype, `Log_event`.
Though to avoid hiding `use-of-uninitialized-value` mistakes in the
future, leaving unset fields uninitialized is more assured;
not to mention the potential of ID 0 still in use.

Reviewed-by: Brandon Nesterenko <brandon.nesterenko@mariadb.com>
Acked-by: Daniel Black <daniel@mariadb.org>

Author: ParadoxV5

client/mysqlbinlog.cc

@@ -1201,9 +1201,16 @@ Exit_status process_event(PRINT_EVENT_INFO *print_event_info, Log_event *ev,
         binlog, even if they have a server_id.  Also, we have to read
         the format_description event so that we can parse subsequent
         events.
+        Don't skip Unknown events either since we don't know their `server_id`s.
       */
-      if (ev_type != ROTATE_EVENT && is_server_id_excluded(ev->server_id))
-        goto end;
+      switch (ev_type) {
+      case ROTATE_EVENT:
+      case UNKNOWN_EVENT:
+        break;
+      default:
+        if (is_server_id_excluded(ev->server_id))
+          goto end;
+      }
     }
     if ((ev->when >= stop_datetime)
         || (pos >= stop_position_mot))