[Graphics][JSROOT] "%jsroot on" broken in Juypter notebooks

JS based graphics are not visible anymore in Jupyter notebooks (%jsroot on magic). The error from the notebooks is [W 18:37:20.750 NotebookApp] 404 GET /static/scripts/JSRootCore.js?v=20200708183714, but I didn't manage to fix it. A highly suspicious commit is https://github.com/root-project/root/commit/a3d00a5fd3aad33d471074512aa7055d1bfaae35, though I didn't manage to fix the paths.