build: don't require package.json for python import

[ianhi]

Following: https://github.com/jupyterlab/extension-template/blob/6356b296facbd4f9283493a5eab16e24e236407a/template/%7B%7Bpython_name%7D%7D/__init__.py.jinja#L13-L16

I think this is necessary to fix the issues we're having with the conda build

[github-actions[bot]]

:point_left: Launch a Binder on branch ianhi/jupyterlab-vim/conda-build-fix