Put workspace-in-sidecar example into no-ci

The workspace-in-sidecar example has been a relatively
consistent flake in our CI suite. The issue #4169
was created in August describing this problem and
there have been relatively regular reports related to the
example since then. To a first approximation I've found 31
individual instances of the test's failure since May across
24 separate Pull Requests.

Attempts to reduce the flakiness of this example have not
been successful yet. So in order to reduce the amount of noise
in our CI (and hopefully increase overall trust in the suite)
this commit moves the example into the no-ci folder, preventing
its execution, while we continue to try and figure out why it
is so flakey.