Gradient Editor reopens by itself when undoing a gradient edit made on a Shader Graph Gradient input port

Steps to reproduce:

1. Create a new Unity project using the Universal 3D template
2. In the Project window, right-click and select Create > Shader Graph > URP > Lit Shader Graph, then press Enter to accept the name
3. Double-click the created Shader Graph asset to open the Shader Graph window
4. Right-click on empty space in the graph, select "Create Node", search for "Sample Gradient" and press Enter to add the node
5. Click the gradient swatch on the Sample Gradient node's "Gradient" input port to open the Gradient Editor
6. Drag one of the bottom color stops along the gradient bar
7. Close the Gradient Editor with its X button
8. Click into the Shader Graph window and press Ctrl+Z (Cmd+Z on macOS)
9. Observe the Editor

Actual results: The gradient on the input port reverts correctly, but the Gradient Editor window reopens on its own even though it was closed at step 7

Expected results: Undo reverts the gradient on the input port and no window is opened.

Reproducible with versions: 6000.0.0f1, 6000.0.84f1, 6000.3.24f1, 6000.6.0b1, 6000.6.2f1, 6000.7.0b1, 7000.0.0a1

Not reproducible with versions: 6000.6.0a7

Tested on (OS): MacOS Silicon Tahoe 26.6.2