Instanced prims, convert to instances toggle not working

**Describe the bug**
When importing a stage with instance able prims into maya, the prims always end up as instances, even when the "convert to instances" checkbox is unchecked. I would like to import some stages without instancing, this is only possible by removing it from the usd file.

**Steps to reproduce**
choose file->import
Set the file type to usd
pick the the attached usd ( instance.usda)
turn off "Convert to instances"
Import
observe the boxes are still instanced.

**Expected behavior**
When the checkbox is off, I would expect each box to be unique geometry

**Attachments**
instance.zip -> instance.usda, a simple stage to illustrate the problem

**Specs (if applicable):**
- OS & version windows 11
- Compiler & version [e.g. gcc 6.3.1]
- Maya version maya 2023
- Maya USD commit SHA 0.22.0_202301152314-a488582

[instance.zip](https://github.com/Autodesk/maya-usd/files/10572261/instance.zip)