Add Jupyter Collaboration load tests

[cyphercodes]

Summary

• add Jupyter Collaboration to the external test dependencies
• add regression coverage that loads a standalone text notebook through Jupyter Collaboration's DocumentRoom
• add regression coverage that loads a paired ipynb/percent script notebook through DocumentRoom, combining newer text inputs with ipynb outputs

Closes #1544

Tests

• pixi run pytest -q tests/external/contents_manager/test_jupyter_collaboration.py
• pixi run pytest -q tests/integration/contents_manager/test_load_multiple.py tests/external/contents_manager/test_jupyter_collaboration.py
• pixi run pre-commit run --files pyproject.toml pixi.lock tests/external/contents_manager/test_jupyter_collaboration.py

[github-actions]

Thank you for making this pull request.

Did you know? You can try it on Binder: or .

Also, the version of Jupytext developed in this PR can be installed with pip:

HATCH_BUILD_HOOKS_ENABLE=true pip install git+https://github.com/cyphercodes/jupytext.git@test-jupyter-collaboration-1544

(this requires nodejs, see more at Developing Jupytext)

[mwouts]

Hi @cyphercodes , thank you for your PR, great timing! Are you a user of Jupyter collaboration and jupytext ? If so what's your experience with them ? Thanks !