Scene view stops filtering by the Hierarchy search after exiting Play Mode when a second Hierarchy window is present in the layout

Steps to reproduce:

1. Create a new project using the 3D URP template
2. In the Hierarchy, type in anything (e.g. "global")
3. Observe the Scene view is dimmed (only GameObjects from search results are shown)
4. Enter and exit Play mode
5. Observe Scene view remains dimmed and search remains in Scene view
6. Anywhere in the Editor add another Hierarchy tab (e.g. Window > General > Hierarchy)
7. Enter and exit Play mode again
8. Observe the Scene view

Actual results: The Scene view is no longer dimmed, although the search query remains in the Hierarchy

Expected results: The Scene view remains dimmed

Reproducible with versions: 6000.6.0a1, 6000.6.0f1, 6000.7.0a6

Not reproducible with versions: 6000.3.22f1, 6000.5.0a7, 6000.5.10f1

Tested on (OS): macOS 26.5, Ubuntu 20.04

Notes:

• Does not reproduce with legacy hierarchy
• The second Hierarchy window does not need to be focused or visible — it only needs to exist in the layout