Fix to remove potential memory leak on Jupyter Server ZMQChannelHandler code

[Vishwajeet0510]

This PR is in reference with PR #6251. Since similar issue is observed on Jupyter Server side as well, creating this PR to resolve the issue here.

@kevin-bates and @blink1073 please review the PR and do the needful. Thanks for all the help :)

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[codecov-commenter]

Codecov Report

Merging #682 (9b4f3c7) into main (87ab9bb) will increase coverage by 0.06%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##             main     #682      +/-   ##
==========================================
+ Coverage   77.80%   77.87%   +0.06%     
==========================================
  Files         110      110              
  Lines       10464    10465       +1     
  Branches     1404     1405       +1     
==========================================
+ Hits         8142     8150       +8     
+ Misses       1930     1921       -9     
- Partials      392      394       +2     

Impacted Files	Coverage Δ
jupyter_server/services/kernels/handlers.py	61.11% <50.00%> (-0.15%)	⬇️
jupyter_server/tests/services/kernels/test_api.py	96.52% <0.00%> (+1.38%)	⬆️
jupyter_server/services/kernels/kernelmanager.py	82.53% <0.00%> (+1.90%)	⬆️

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[blink1073]

Thank you!

[blink1073]

Running script "['pre-commit run --all-files']" on behalf of "blink1073"

[welcome]

Congrats on your first merged pull request in this project! 🎉

Thank you for contributing, we are very proud of you! ❤️

[kevin-bates]

Thank you @Vishwajeet0510 for your contribution and @blink1073 for handling this so quickly!