fix(blob): handle pdf type correctly in ensureBlob

[Yizack]

This PR fixes #391

For testing

1. Run dev server
2. Open playground/server/api/blob/index.put.ts
3. Add ensure options to the handleUpload method

ensure: {
   types: ['pdf']
},

4. Go to http://localhost:3000/blob
5. Try uploading a pdf file

[atinux]

Thank you!

[pkg-pr-new]

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npm i https://pkg.pr.new/nuxt-hub/core/@nuxthub/core@392

commit: fa10993