Clear and concise description of the problem

Currently process.env.NODE_ENV gets replaced by its actual value when vitest is run in browser mode.

This behaviour defeats some parts of component testing, when we want to actually test the behaviour of our component in different environments. Eg: by throwing in development vs warning in production.

Suggested solution

Allow process.env to be dynamic in browser mode

Alternative

No response

Additional context

If you need a quick testing example 🙃
https://github.com/JCQuintas/vitest-browser-process-env

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.