fix: run htmlFallbackMiddleware for no accept header requests

[sapphi-red]

Description

fixes #9520
fixes #15022

Additional context

https://github.com/bripkens/connect-history-api-fallback does this check.
https://github.com/bripkens/connect-history-api-fallback/blob/74564d61c2db06e302923a23bd459bb5dd91712b/lib/index.js#L11-L43

I also think this middleware should not check Accept: application/json. But I didn't change that because this part also comes from connect-history-api-fallback and didn't want to change the behavior much.

---

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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[sapphi-red]

/ecosystem-ci run

[vite-ecosystem-ci]

📝 Ran ecosystem CI on 8e8a5bb: Open

suite	result	latest scheduled
analogjs	✅ success	✅ success
astro	✅ success	✅ success
histoire	❌ failure	❌ failure
ladle	✅ success	✅ success
laravel	❌ failure	❌ failure
marko	✅ success	✅ success
nuxt	✅ success	❌ failure
nx	❌ failure	❌ failure
previewjs	✅ success	✅ success
qwik	❌ failure	❌ failure
rakkas	✅ success	✅ success
sveltekit	❌ failure	❌ failure
unocss	✅ success	✅ success
vike	✅ success	✅ success
vite-plugin-pwa	✅ success	✅ success
vite-plugin-react	✅ success	✅ success
vite-plugin-react-pages	✅ success	✅ success
vite-plugin-react-swc	✅ success	✅ success
vite-plugin-svelte	✅ success	✅ success
vite-plugin-vue	✅ success	✅ success
vite-setup-catalogue	✅ success	✅ success
vitepress	✅ success	✅ success
vitest	✅ success	✅ success

[bluwy]

I'm ok with this if this is the more expected behaviour from users 👍

I'm also fine with removing the application/json check. From connect-history-api-fallback, I found that it's added because some people don't expect HTML files to be served for application/json;*/*, and some expect otherwise #9520 (comment). But I don't think this is an issue for us.

[mxxk]

Thanks for this fix! I stumbled upon it due to a case where Accept was present but contained application/json. In this instance, Vite was pinged with Accept: text/html, application/json, text/plain, */*, which was okay in Vite 4.5.0, but resulted in 404 in Vite 5.0.0 due to #14756.

For what it's worth, the Accept header was generated by cypress-io/github-action.

[sapphi-red]

@mxxk That case should be fixed by #15059 which is released in v5.0.2. If it is still failing after upgrading the version to v5.0.2, please create a new issue with a minimal repro.

[mxxk]

Whoops, I forgot to mention in #15025 (comment) that I verified that the problem is fixed in Vite 5.0.2. ✅

The original intent behind the comment was to capture what seemed like a different case from a missing Accept header (as stated in the two issues #9520 and #15022 fixed by this PR). However, as you pointed out, in my case, the fix came from #15059. Thank you for clarifying @sapphi-red!