Disable un-needed contentBase for webpack-dev-server

Merged Thong Kuah requested to merge disable_content_base into master

What does this MR do?

Disable un-needed contentBase for webpack-dev-server

We don't need https://webpack.js.org/configuration/dev-server/#devservercontentbase

Related issue: https://gitlab.com/gitlab-org/gitlab/-/issues/246961

Edited by Thong Kuah