Resolve warning on port binding

[jackgerrits]

Why are these changes needed?

Instead of getting a free port using binding instead relies on the functionality of jupyter kernelgateway

Related issue number

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

Attention: Patch coverage is 0% with 9 lines in your changes are missing coverage. Please review.

Project coverage is 46.81%. Comparing base (a54b733) to head (29e0a02).

Files	Patch %	Lines
autogen/coding/jupyter/local_jupyter_server.py	0.00%	9 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1870       +/-   ##
===========================================
+ Coverage   36.03%   46.81%   +10.78%     
===========================================
  Files          63       63               
  Lines        6618     6619        +1     
  Branches     1459     1585      +126     
===========================================
+ Hits         2385     3099      +714     
+ Misses       4039     3270      -769     
- Partials      194      250       +56     

Flag	Coverage Δ
unittests	46.74% <0.00%> (+10.70%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[ekzhu]

Confirmed it works on windows