Testbed quality of life improvement: Stream docker to console.

[afourney]

Why are these changes needed?

Previously testbed logs were printed only after the scenario had completed, and Docker exited. However, scenarios often were very long, and could take minutes to conclude. If watching a test in real-time, this was a long time to wait to see how the task was going.

This PR turns on Docker streaming, and allows you to monitor experiments in real-time.

Related issue number

N/A

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (3a768c3) 26.63% compared to head (0e61254) 26.63%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #947   +/-   ##
=======================================
  Coverage   26.63%   26.63%           
=======================================
  Files          28       28           
  Lines        3777     3777           
  Branches      858      858           
=======================================
  Hits         1006     1006           
  Misses       2700     2700           
  Partials       71       71           

Flag	Coverage Δ
unittests	26.58% <ø> (ø)

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[afourney]

Superseded by #1048