"TextureMaker only supports one CreateTextureNode" warning appears when recreating a node after undoing its initial creation

Steps to reproduce:

1. Create new Unity project
2. Install “com.unity.graphtoolkit-samples” package using Package Manager 
3. Go to Samples tab and import “TextureMaker Sample” sample
4. Navigate to Assets > Create > Graph Toolkit Samples > Texture Maker Graph
5. Open “New Graph.texmkr” Asset
6. Right-click in the graph, select Add Node > Create Texture Node
7. Undo the creation with Ctrl+Z/Command+Z
8. Right-click in the graph, select Add Node > Create Texture Node
9. Observe the node UI and Console

Actual results: A warning is shown stating "Assets/New Graph.texmkr: TextureMaker only supports one CreateTextureNode by graph. Only the first created one will be used."

Expected results: No warning is shown. Undoing the initial node creation should completely clear it from the graph's state, allowing a new one to be created without conflict

Reproducible with versions: 6000.4.3f1
Not reproducible with versions: 6000.5.0b4, 6000.6.0a2

Tested on (OS): macOS 26.4

Notes:

• Could not find an already reported ticket suggesting it was fixed