Fix search tickets method

Following the suggestions of https://gitlab.com/rhab/PyOTRS/-/issues/29

We need this custom config to solve the problem with the search ticket method. We need to send a POST method instead of a GET method. The change is:

  TicketSearch:
    RequestMethod:
    - GET
    Route: /Ticket

to:

  TicketSearch:
    RequestMethod:
    - POST
    Route: /TicketSearch

This change also needs a change in the OTRS web service connector config. Please use the Generic Interface Connector provided by PyOTRS: https://gitlab.com/rhab/PyOTRS/-/blob/master/webservices_templates/GenericTicketConnectorREST.yml.