manual usd export affects the presence of GeomSubsets in the file

**Describe the bug**
depending on how the export from maya is performed the resulting UDS file may or may not contain GeomSubsets with identical export settings. There seems to be no way to control it and it is not saved to the maya scene but only persists in the session.

**Steps to reproduce**
1. start fresh maya session, create a poly cube and use mel/python to export to USD. The file will contain each face as `GomSubset`
2. export the same sphere using the menu file->export with the same settings.
3. run the exact same mel/python as in point 1. The resulting USD will have no GeomSubsets this time.

`file -force -options ";exportUVs=1;exportSkels=none;exportSkin=none;exportBlendShapes=0;exportDisplayColor=0;;exportColorSets=1;exportComponentTags=1;defaultMeshScheme=none;animation=0;eulerFilter=0;staticSingleSample=0;startTime=1;endTime=1;frameStride=1;frameSample=0.0;defaultUSDFormat=usdc;parentScope=;defaultPrim=GEO;shadingMode=useRegistry;convertMaterialsTo=[];exportRelativeTextures=automatic;exportInstances=1;exportVisibility=1;mergeTransformAndShape=1;stripNamespaces=0;worldspace=0;excludeExportTypes=[]" -typ "USD Export" -pr -es "C:/temp/geo.usd";`

**Expected behavior**
python/mel export that provides all settings for the exporter should not be affected by some global session variable and should generate identical USD each time.
an option to include GeomSubsets would be a welcome addition as in most cases we do not want them.

**Attachments**
demonstration: [youtube](https://youtu.be/ydvNfwWiMmQ)

**Specs (if applicable):**
- Windows 10
- maya 2024
- USD plugin 0.27.0 and 0.28.0