We add a step to build help center and then test the broken links as we
used to before removing the test temporarily.
This commit focuses on just adding back the broken link checks for the
help center. We skip the fragment check since that is in-built in
starlight and starlight tests account for that already. For the image
check we can add it back in a followup issue.
This directory contains scripts that are used in building, managing,
testing, and other forms of work in a Zulip development environment.
Note that tools that are also useful in production belong in
scripts/ or should be Django management commands.
a766c092fc