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.

TypeFox/jupyterlab,eskirk/jupyterlab,jupyter/jupyterlab,eskirk/jupyterlab,charnpreetsingh185/jupyterlab,jupyter/jupyterlab,jupyter/jupyterlab,TypeFox/jupyterlab,charnpreetsingh185/jupyterlab,eskirk/jupyterlab,eskirk/jupyterlab,charnpreetsingh185/jupyterlab,jupyter/jupyterlab,TypeFox/jupyterlab,eskirk/jupyterlab,jupyter/jupyterlab,TypeFox/jupyterlab,TypeFox/jupyterlab,charnpreetsingh185/jupyterlab,charnpreetsingh185/jupyterlab