Mermaid Preview in Markdown preview is not working

[eneufeld]

Bug Description:

I use this extension: https://open-vsx.org/extension/bierner/markdown-mermaid in VSCode to preview Mermaid diagrams while I create them.
I want to use the same extension in Theia. Unfortunately no preview of the diagram is shown.

Steps to Reproduce:

1. Install https://open-vsx.org/extension/bierner/markdown-mermaid
2. Create new markdown file with mermaid diagram inside
3. open markdown preview
4. don't see a diagram

Additional Information

• Operating System: Ubuntu 22.04.5 LTS
• Theia Version: Version 1.57.0