Adding a Light Anchor component throws an exception when no Game View is open

Steps to reproduce:

1. Create a new URP 3D project via Unity Hub
2. Close every open Game View tab/window.
3. Create a GameObject, select it, and add a Light Anchor component via the Inspector's Add Component button

Actual results: The Console immediately logs an InvalidOperationException: "Sequence contains no elements", thrown from LightAnchorEditor.OnEnable - then cascades into repeated NullReferenceExceptions from LightAnchorEditor.OnInspectorGUI every time the Inspector repaints afterward (a burst of about 7 exceptions total right when the component is added).

Expected results: Adding a Light Anchor component should not throw, regardless of whether a Game View window is currently open.

Reproducible with versions: 6000.0.0f1, 6000.0.85f1, 6000.3.25f1, 6000.6.3f1, 6000.7.0b2, 7000.0.0a1

Tested on (OS): Windows 11