Cannot export Point bone under a Biped

**Describe the bug**

While a Biped is usually our base to skin characters, we often add other controller in our rigs like Point. The USD exporter does not seem to export any other object representing bones when they are nested inside a Biped.

In this scene:
- `Root_001` holds a hierarchy of `BoneGeometry`, `Place`, `Point`, `EditablePoly` then `Biped`. Those types of objects are used by our riggers to make their character rigs.
- `Root_002` holds a `Biped`, but there is a `Point` nested directly under the root Biped bone

When exporting this scene to USD with these options:

- The skeleton under `Root_001` is properly exported: the bones are exported regardless of their type, and the Biped hierarchy is also present
- The Biped under `Root_002` is exported, *but the nested point `F_Point_InABiped` is nowhere to be found

**Steps to reproduce**
Steps to reproduce the behavior:
1. Open the attached scene [debug-bone-types.zip](https://github.com/user-attachments/files/30284816/debug-bone-types.zip)
2. Export USD with the options above
3. Inspect the USD
4. ERROR: the joint `F_Point_InABiped` is not exported

**Expected behavior**

The joint `Bip001/Bip001_Pelvis/F_Point_InABiped` should be present in `/Root_002/Reference`

**Attachments**
If applicable, add screenshots, sample files, etc to help explain your problem.

**Specs (if applicable):**
- OS & version: Windows 11
- 3ds Max version: 3ds Max 2024
- 3ds Max USD version: v0.15.0.14

Start with the attached debug-bone-types.zip scene and reproduce the USD export using the issue's documented options. Inspect the resulting USD and compare the two roots; done means the joint F_Point_InABiped appears at /Root_002/Reference alongside the exported Biped hierarchy.

Written by the indexing model from the issue text.