Support interactive cpp and python tests

We want to have cpp tests that link against usd in order to do interactive renders (while changing the scene).
At the moment, the tests are failing to link properly so we can't do it

Start by reproducing the failing C++ and Python test setup described in the issue, then inspect how those tests link against USD. Confirm the expected interactive-render workflow and verify that the tests link successfully and support scene changes without failures.

Written by the indexing model from the issue text.