PDF export fetches assets from cloudflare

[b1-luettje]

Bug Report

Problematic behavior

When exporting/downloading a note that contains emojis, corresponding assets (.png) are fetched from cdnjs.cloudflare.com

Expected behavior/code

• I am able to host any instance without having to allow external connections
• All assets required for export are bundled inside the application or fetched on demand by from backend

Steps to Reproduce

1. Create a new note
2. Insert any emoji
3. Click the download button and observe the network request

Environment

• Docs version: beta I guess?
• Instance url: https://impress-preprod.beta.numerique.gouv.fr/docs/53789cc9-4ab8-43ee-ad52-6caebab0a79f/

Possible Solution

Additional context/Screenshots

[AntoLC]

Linked to #1337

[AntoLC]

Linked to #1436