[EMSUSD-103] Unshareable stage toggle altering the stageTargetLayer

I am encountering an issue where my active stageTargetLayer on a mayaUsdProxyShape is not being restored upon file open, when the stage is set to unshareable. My suspicion is that the issue stems from how the Shareable toggle is working. As you can see in my example below, simply toggling the Shareable attribute on the node, changes the stageTargetLayer, which seems like unwanted behaviour:


I would expect that toggling the shareable attribute would not affect the current stageTargetLayer. Furthermore, I would expect that my stageTargetLayer be restored upon file open, when the stage is set to unshareable.

Specs:
CentOS 7
Maya 2023.3
Maya USD: 0.23.0
Pixar USD: 22.11