There isn't any UI observable behavior of the dragend of the waypoint,
but we can test that the backend was called. The only uncovered parts of
that component are now error paths, but the error handling in that
component is to just ignore errors, so there's also nothing to test
there.
A serverconfig.env (or just environment variables) can be set to
override the default bind address/port for the backend. This is passed
to the front end as a query parameter.
