Advanced playground should use JSON instead of XML on reload

[BeksOmega]

Category

• Plugins

Component

Advanced playground

Describe the bug

The playground still uses XML serialization on reload, so if you test out readOnly mode, your blocks get stuck as readonly. The JSON serializer doesn't have this problem, so we should witch to using that.

To Reproduce

Steps to reproduce the behavior:

1. Go to the advanced playground.
2. Add some blocks to the workpace.
3. Switch to readonly mode.
4. Switch out of readonly mode.
5. Observe how your blocks are still readonly.

Expected behavior

Playground should use JSON serialization to avoid this problem