Steps to reproduce:

1. Create a new URP project
2. Create a new Lit Shader Graph (Assets > Create > Shader Graph > URP > Lit Shader Graph)
3. Right-click and add Sample Gradient node
4. Click on the Color Picker property next to Gradient (G)
5. Observe the HDR Gradient Editor window opens
6. Change any value, color or mode
7. Click Ctrl+Z shortcut to undo
8. Observe the HDR Gradient Editor window

Actual results: The HDR Gradient Editor window closes immediately after Ctrl+Z is pressed, although the value is correctly undone 

Expected results: The HDR Gradient Editor window remains open and the last gradient change is undone

Reproducible with versions: 6000.0.43f1, 6000.0.75f1, 6000.3.15f1, 6000.4.7f1, 6000.5.0b8, 6000.6.0a5

Not reproducible with versions: 6000.0.42f1 (HDR Gradient Editor window would not close but undo also did not correctly update state in the Gradient Editor window)

Tested on (OS): Windows 11

Notes:

• On 6.0, if undo is pressed while the Color Picker is open - "Destroying object multiple times. Don't use DestroyImmediate on the same object in OnDisable or OnDestroy.

UnityEditor.EditorApplication:Internal_CallUpdateFunctions ()" error gets thrown

• Does not reproduce with other Gradient editors in the Editor