karma-sinon-chai is not compatible with Chai 5+, and Karma is no longer
being updated.
Load sinon and chai manually instead, until we can have a long term plan
in place.
This is extra important in the tests where we expect no changes to the
display, as otherwise we can't tell the difference between success and a
decoder that is simply waiting for more data.
These are very pointless for the server to send, but not a violation of
the protocol so we need to be able to handle them. We've seen this
happen in real world scenarios a few times.
Pierre Ossman