Remove hardcoded client install in CI (#1019)

Author: blink1073

.github/workflows/python-tests.yml

@@ -121,7 +121,6 @@ jobs:
           pip check
       - name: Run the tests
         run: |
-          pip install jupyter_client@https://github.com/blink1073/jupyter_client/archive/refs/heads/synchronous_managers.zip
           pytest -vv -W default || pytest -vv -W default --lf
 
   make_sdist: