Merge branch 'fix_ipywidgets' into 'master'

Add constraint for older py-ipywidgets

See merge request technical-coordination/project-internal/devops/platform/ebrains-spack-builds!337

spack.yaml

@@ -6,6 +6,8 @@ spack:
     - py-ipykernel
     - py-notebook
     - py-ipycanvas
+    # "collab"-specific constraint to match ("jupyterlab_widgets") in the base image
+    - py-ipywidgets@:7.7
     # Collab utils
     - clb-nb-utils@0.1.0
     # EBRAINS tools