Summary:
`webpack-dev-server` depends on `http-proxy-middleware` which depends on a version of `http-proxy`
with a security bug. This forces an upgrade on `http-proxy-middleware` to patch the vuln.

Test Plan: Running the UI still works.

Reviewers: zasgar, michelle, nick, #engineering

Reviewed By: zasgar, #engineering

Differential Revision: https://phab.corp.pixielabs.ai/D6679

GitOrigin-RevId: ecee9082e13cb1e11378ac5a47d0fb7f7a9765ea