Encoding issues in broadcast messages

[mathilde-cryptpad]

Description

Broadcast messages have an encoding issues.

Steps to reproduce

1. Create a broadcast message from /admin/#broadcast
2. Preview it
3. Receive the test notification
4. Click on it
5. Witness the l'utilisation encoding issue

Relevant logs

None

Expected behavior

UTF-8 should be fully supported in broadcast messages.

Which operating system are you using?

Linux/BSD/UNIX, Microsoft Windows, Apple macOS, Apple iOS, Google ChromeOS, Google Android

What browsers are you seeing the problem on?

Mozilla Firefox, Google Chrome, Apple Safari, Microsoft Edge

Extensions

Not relevant

Version

5.6.0