fix(cloudflare-pages): use predefined wildcards in routes.exclude

[pgraug]

🔗 Linked issue

❓ Type of change

• 📖 Documentation (updates to the documentation, readme, or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

When using Cloudflare Pages with Nitro all static files need to be present in the _routes.json file's exclude array.

Since only 100 entries are allowed in the file, projects can use wildcards to reduce the number entries (eg. excluding "/_nuxt/*" excludes all subpaths).

Nitro handles this well for nitro.options.publicAssets by adding the wildcard path and then not adding the individual files matching it. But if you just add a wildcard to nitro.options.cloudflare.pages.routes.exclude it still includes the individual files like so:

{
  "version": 1,
  "include": ["/*"],
  "exclude": [
    "/cf-pages-exclude/*",
    "/cf-pages-exclude/not-in-routes-json.txt",  <-- This shouldn't be here
    ...
  ]
}

That's what this PR fixes. It handles both cases using routes.exclude (that explicitPublicAssets has already been appended to) for the globby ignore list, replacing the "/*" syntax used on Cloudflare Pages with the "/**" syntax that globby uses.

I added a test that fails without the fix.

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[pi0]

Thanks!