docs: public Principal getAuthenticationPrincipal(final String ticketGrantingTicketId) {
          try {
              val ticketGrantingTicket = this.centralAuthenticationService.getTicket(ticketGrantingTicketId, TicketGrantingTicket.class);
              return ticketGrantingTicket.getAuthentication().getPrincipal();
          } catch (final InvalidTicketException e) {
              LOGGER.warn("Ticket-granting ticket [{}] cannot be found in the ticket registry.", e.getMessage());
              LOGGER.debug(e.getMessage(), e);
          }
          LOGGER.warn("In the absence of valid ticket-granting ticket, the authentication principal cannot be determined. Returning [{}]", NullPrincipal.class.getSimpleName());
          return NullPrincipal.getInstance();
      }