Panels using the Discrete visualization are blank

[AgnesToulet]

What happened:
Rendering panels using the Discrete plugin are blank.

What you expected to happen:
The rendered panel should show the same thing as the dashboard view.

How to reproduce it (as minimally and precisely as possible):
Create a panel using the Discrete plugin visualization and click on Share > Direct link rendered image.

Anything else we need to know?:

Environment:

• Grafana Image Renderer version: 3.7.0
• Grafana version: 9.4.7
• Installed plugin or remote renderer service: Remote renderer service
• OS Grafana Image Renderer is installed on: Windows (but reproduced on Linux)
• User OS & Browser: Windows & Chrome
• Others: