CAPI: Confirm we do have a "Pressing Update whilst in progress does nothing" check

Reviewing #1773 I realised that we might have lost any 'latching' on not being able to trigger a fresh 'station' set of CAPI queries if they're already in progress.

So, check that, and re-implement if it's not there.

Start by tracing the CAPI station-query flow and the Update action mentioned in the issue. Verify whether pressing Update while a station query set is already in progress is prevented from starting another set. Done means the existing no-op behavior is confirmed by a test, or the latching is restored and covered by one.

Written by the indexing model from the issue text.