Adding new points to Path2D and undoing it breaks scene history

[KoBeWi]

Tested versions

Regression from #86542

System information

Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1060 (NVIDIA; 31.0.15.4633) - Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz (8 Threads)

Issue description

When you add a new Path2D and add points to it and then undo it, the scene history breaks and you can't do anything until you reload the scene.

Steps to reproduce

1. Create new scene
2. Add Path2D
3. Ctrl + Click somewhere to add points
4. Undo
5. The scene is unusable

Minimal reproduction project (MRP)

N/A

[naturally-intelligent]

I'm getting basically unusable Path2Ds in 4.3dev5, once I add a point to the path they go dead, ex can't add child nodes to Path2D

Existing untouched path2D nodes made in prior versions still work

[djrain]

Not sure if I should make a new issue, but same bug is present in 4.3 stable if you add a point by clicking on the curve with the "select points" tool.

[Calinou]

Not sure if I should make a new issue, but same bug is present in 4.3 stable if you add a point by clicking on the curve with the "select points" tool.

Please open a new issue for this, as the cause may be different.