Draft: [MCCS-1780] Cannot stop beam data

After a change in aavs-system pending_data_requests now returns the type of data request thats streaming, as we can have two data streams at a time, one of any of the 5, we check to see if the data type requested is already running, or if two are running. If not then we can make the request

Relies on ska-telescope/aavs-system!87 (closed) being merged for the bug to be fixed