fix(html): externalize rollup.external scripts correctly

[sapphi-red]

Description

This PR fixes two bugs:

• <script type="module"> with the src externalized by rollupOptions.external was throwing an error (it didn't error before fix: set scripts imported by HTML moduleSideEffects=true #18411)
  • this fix should fix storybook in ecosystem-ci
• <script type="module"> with the src externalized by rollupOptions.external was not preserved in the output HTML
  • I found this when I wrote the test

[sapphi-red]

/ecosystem-ci run

[vite-ecosystem-ci]

📝 Ran ecosystem CI on 7eea400: Open

suite	result	latest scheduled
astro	❌ failure	❌ failure
histoire	❌ failure	❌ failure
marko	❌ failure	❌ failure
redwoodjs	❌ failure	❌ failure
remix	❌ failure	❌ failure
storybook	✅ success	❌ failure
sveltekit	❌ failure	❌ failure
vike	❌ failure	❌ failure
vite-plugin-react	❌ failure	❌ failure
vite-plugin-svelte	❌ failure	❌ failure
vite-plugin-vue	✅ success	❌ failure
vitest	❌ failure	❌ failure

✅ analogjs, ladle, laravel, nuxt, previewjs, quasar, qwik, rakkas, unocss, vite-environment-examples, vite-plugin-pwa, vite-plugin-react-swc, vite-setup-catalogue, vitepress, vuepress