why are Flask dependencies installed on Django build?

[Example Job](https://github.com/honeybadger-io/honeybadger-python/actions/runs/4573494993/jobs/8074000607)

Or more specifically, why does this [script](https://github.com/honeybadger-io/honeybadger-python/blob/master/scripts/install_frameworks.sh) blindly install Flask dependencies--and even Flask itself--when $FLASK_VERSION isn't set.