refactor: remove acorn

[sapphi-red]

Description

Rollup v4 doesn't use acorn and exposes parseAst. This PR removes acorn by using that function instead.

• package size: 828.6 kB -> 772.2 kB
• unpacked size: 3.6 MB -> 3.3MB

Additional context

---

What is the purpose of this pull request?

• [ ] Bug fix
• [ ] New Feature
• [ ] Documentation update
• [x] Other

Before submitting the PR, please make sure you do the following

• [x] Read the Contributing Guidelines, especially the Pull Request Guidelines.
• [x] Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• [x] Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• [x] Update the corresponding documentation if needed.
• [ ] Ideally, include relevant tests that fail without this PR but pass with it.

[bolt-new-by-stackblitz[bot]]

Run & review this pull request in StackBlitz Codeflow.

[sapphi-red]

/ecosystem-ci run

[vite-ecosystem-ci[bot]]

📝 Ran ecosystem CI on 70f5422: Open

suite	result	latest scheduled
nuxt	:x: failure	:white_check_mark: success

:white_check_mark: analogjs, astro, histoire, ladle, laravel, marko, previewjs, quasar, qwik, rakkas, remix, sveltekit, unocss, vike, vite-plugin-pwa, vite-plugin-react, vite-plugin-react-pages, vite-plugin-react-swc, vite-plugin-svelte, vite-plugin-vue, vite-setup-catalogue, vitepress, vitest

[vite-ecosystem-ci[bot]]

📝 Ran ecosystem CI on 70f5422: Open

:white_check_mark: analogjs, astro, histoire, ladle, laravel, marko, nuxt, previewjs, quasar, qwik, rakkas, remix, sveltekit, unocss, vike, vite-plugin-pwa, vite-plugin-react, vite-plugin-react-pages, vite-plugin-react-swc, vite-plugin-svelte, vite-plugin-vue, vite-setup-catalogue, vitepress, vitest

[bluwy]

The flaky CI fails is happening in main too. I'm investigating this and will submit a fix later. Merging this for now.