Make sure new CSS compiler respects HMR setting

What does this MR do and why?

Make sure new CSS compiler respects HMR setting

We run tests in CI with vite (e2e:test-on-gdk). When these run in CI, we do not need to watch our CSS assets, because the CSS is not going to be changed during the run of the pipeline. Therefore we just make the CSS compiler respect the hot module reloading setting.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

N/A

How to set up and validate locally

N/A