py-jupyterlab: updated to 4.0.12

4.0.12

Bugs fixed

- Fix jupyterlab downgrade issue on extension installation
- Fix search highlights removal on clearing input box
- Add scroll margin to headings for better alignment
- Fix shortcut UI failing on filtering when empty command is given
- Fix connection loop issue with standalone foreign document in LSP
- Fix outputarea package from not detecting updates

Maintenance and upkeep improvements

- Backport: Fix visual tests

Documentation improvements

- Remove Python 3.0, Notebook 5 mentions from contributor docs

(adam)