[EMSUSD-2222] Duplicating a ProxyStage and hiding the duplicate causes Maya to Crash

[santosg87]

Tested on mayausd 0.28, now save scene after duplicate usd proxy doesn't crash maya. However, now after duplicate, if we hide the duplicated usd proxy, maya will crash.

New steps:

1. Create a USD proxy node (Create -> Universal Scene Description (USD) -> Stage with New Layer).

2. Duplicate the USD proxy node (select the node and then Ctrl + D).

3. Hide the duplicated USD proxy.

Originally posted by @sylvieChen in #3283

[sbissonnette]

We are having this issue on our end as well

Tested on: Maya 2024.2 + mayaUsd 0.30.0