Fixes#30451.
In a case that both `--help-center` and `--help-center-dev-server`
flags are passed to `run-dev`, `--help-center` flag will take
precedence without throwing any error.
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.