There is no way to remove a Sub Scene when the Entities package is removed

Steps to reproduce:

1. Create a new Unity project and install the Entities package
2. Enable the New Hierarchy from Settings > General > New Hierarchy > Use new Hierarchy window
3. Create a new Sub Scene in the Hierarchy window
4. Remove the Entities package
5. Right click the Sub Scene in the Hierarchy window
6. Observe the context menu

Actual results: There is no way to remove the Sub Scene

Expected results: There is an option to remove the Sub Scene

Reproducible with versions: 6000.3.2f1, 6000.4.0b2, 6000.5.0a3

Could not test with: 6000.0.64f1, 6000.2.15f1, 6000.3.0a1 (due to no Hierarchy V2)

Tested on (OS): MacOS Silicon Tahoe 26.0.1

Notes:

• Deleting the Sub Scene's asset file in the Project Browser does not remove the Sub Scene from the Hierarchy as well
• The issue does not reproduce with the old Hierarchy, only Hierarchy V2