Delete example jupyter-js-ui dependency
Delete example jupyter-js-ui dependency

This conflicts with the jupyter-js-plugin's dependency, and is not needed.

jupyter/jupyter-js-plugins,jupyter/jupyter-js-plugins,blink1073/jupyter-js-plugins,jupyter/jupyter-js-plugins,blink1073/jupyter-js-plugins,jupyter/jupyter-js-plugins,blink1073/jupyter-js-plugins,jupyter/jupyter-js-plugins,blink1073/jupyter-js-plugins,blink1073/jupyter-js-plugins