Localization: saving a custom locale outside the project throws an exception and discards the entered name and identifier

Steps to reproduce:

1. Create a new project
2. Install the Localization package (com.unity.localization)
3. Open Edit > Project Settings > Localization and click "Create" to make the settings asset
4. Click "Add Custom Locale", enter a name and an identifier that is not already in use
5. Click "Create" and save to a location outside the project - for example the Desktop
6. Check the Console, then look for the "Add Custom Locale" window

Actual results: The save dialog accepts the external location with no warning. An exception is logged to the Console, and no Locale asset is created - neither in the project nor at the chosen location. The "Add Custom Locale" window has already closed, so the name and identifier that were entered are gone and must be retyped from scratch

Expected results: Either the save dialog restricts selection to locations inside the project, or the failure is reported, and the window stays open with the entered values preserved so the user can retry

Reproducible with versions: 1.5.12 (6000.5.7f1, 6000.6.0f1, 6000.7.0a6)

Tested on (OS): MacBook Pro - Tahoe 26.6.2

Notes:

• Two failures in one action: the operation throws instead of validating the location, and the window closes regardless of the outcome, so the user's input is discarded on failure