very small bug on default prim

**Describe the bug**
In the export option "include Namespaces" does not update name on "default prim"

**Steps to reproduce**
Steps to reproduce the behavior:
1. selection a object with namespace
2. Click on export selection-->USD
3. Select default prim by menu
4. uncheck "include namespace" on advanced menu and export
5. read usd file:

**Expected behavior**
the default prim name strip namespace when the option "include namespace" is uncheck

**Specs (if applicable):**
- Windows 11
- Maya 2024.2
- Maya USD plugin 0.30

**Additional context**
This bug does not affect the integrity of the file and its readability, in Maya and Houdini all works good, its just about a clean write

thank you