History fallback silencing 404

[AlexandreBonaventure]

Describe the bug

History may require some tweaking because it is silencing regular 404 when importing .js files for instance.
Here for instance someone may mistype an import name https://github.com/jamiealex/vite-history-fallback/blob/master/App.vue#L7
And instead of returning of 404, letting the dev know he messed up it is giving the index.html.
Chrome is throwing an error here: Failed to load module script: The server responded with a non-JavaScript MIME type of "text/html". Strict MIME type checking is enforced for module scripts per HTML spec. but it could be more explicit IMO.
I know this could be handled by eslint/third party dev tools but I genuinly think we should not rely on that. To know whether the response should fallback we could maybe check for ?import query string or other metadata.

Reproduction

https://github.com/jamiealex/vite-history-fallback

[AlexandreBonaventure]

I actually found a Chrome Bug where Failed to load module script: The server responded with a non-JavaScript MIME type of "text/html". Strict MIME type checking is enforced for module scripts per HTML spec. is sometimes not thrown.... thus my issue ...