NullReferenceException is thrown and an Action remains visible when undoing Action Map creation

Steps to reproduce:

1. Create a new URP project
2. Go to Assets > Create > Input Actions
3. Open the created .inputactions
4. Click the + button next to Action Maps
5. Click Ctrl+Z shortcut to undo creation
6. Observe the Console and the Input Actions Editor

Actual results: "NullReferenceException" is thrown and an Action is still visible in the Input Actions Editor even though the Action Map creation was undone

Expected results: No errors and all Actions should be removed with the Action Map

Reproducible with versions: 6000.6.0a1, 6000.6.0a4

Not reproducible with versions: 6000.4.6f1, 6000.5.0a7, 6000.5.0b7

Tested on (OS): Windows 11

Notes:

• Input System package version does not seem to be related to reproduction
• Action gets removed when reopening the Input Actions Editor