Don't bail early when running all tests

[fcollonval]

Follow-up of https://github.com/jupyterlab/lumino/actions/runs/9294642763/job/25580176911?pr=706

Tests were skipped due to a failure in one of the package:

 >  Lerna (powered by Nx)   Running target test:webkit for 16 projects failed

   Tasks not run because their dependencies failed or --nx-bail=true:
   
   - @lumino/application:test:webkit
   - @lumino/polling:test:webkit
   
   Failed tasks:
   
   - @lumino/datagrid:test:webkit

We should run all tests on the CI to capture all failures at once.