How to reproduce:
1. Create and open a new project
2. Install the Input System package through Window > Package Manager
3. Click Edit > Project Settings > Input System Package > “Create and assign a default project-wide Action Asset“
4. Delete the “UI“ Action Map
5. Select any other section in the Project Settings or close the Project Settings
6. Observe the Console

Expected result: Nothing is logged
Actual result: A warning is logged

Reproducible in: 1.8.2, 1.14.0 (6000.0.46f1, 6000.1.0b14, 6000.2.0a8)
Not reproducible in: 1.8.1 (6000.0.46f1, 6000.1.0b14, 6000.2.0a8), 1.8.2 (2022.3.61f1)
Could not test in: 1.8.2 (2021.3.50f1) (Different Project Settings Layout preventing reproduction)

Reproduced on: Windows 11 Pro (24H2), macOS (15.3.2)
Not reproduced on: No other environment tested

Notes:
- Sometimes Domain Reloads cause the warning to be thrown as well
- When an empty “UI” Action Map exists in the list, similar warnings are thrown about certain missing Actions (if they are missing)
- The start of the warning reads: “InputActionMap with path 'UI' in asset "Assets/InputSystem_Actions.inputactions" could not be found“