Steps to replicate the issue (include links if applicable):
Open PAWS/jupyterlab - create a file or open a file.

What happens?:
No warning appears

What should have happened instead?:
PAWS should warn users about adding credentials to files in PAWS

Software version (skip for WMF-hosted wikis like Wikipedia):

Other information (browser name/version, screenshots, etc.):
See https://phabricator.wikimedia.org/T330028