On-demand update of swiss public transport sensor (#16723)

* Sensor values to be updated only when required (only after the train has crossed).
Looking at the documentation on https://transport.opendata.ch/docs.html, delay information is available only on stationboard, so no need to query often if there is no "real"time info.

* Bumping up version of python_opendata_transport to 0.1.4 in order to catch client errors like throttling rejection (HTTP 429)

* pleasing the hound

* bumping python_opendata_transport to 0.1.4