Children bones are not available to select when selecting a bone to use as a Root node

Reproduction steps:
1. Open the “ReproProject“ project
2. Select the “Assets/rig/male1“ Model in the Project window
3. Observe the “Root node“ Parameter’s dropdown in the Inspector window

Expected result: Children bones under the “humanoid_rig“ bone are available to select
Actual result: No children bones are available to select

Reproducible with: 2023.2.0a15, 2023.2.4f1, 2023.3.0a19
Not reproducible with: 2021.3.33f1, 2022.3.16f1, 2023.2.0a14
Fixed in: 2023.3.0b1

Reproducible on: Windows 11 Pro (22H2)
Not reproducible on: No other environment tested