Avoid namespace collisions when running in parallel
What does this MR do and why?
This MR is part of a series of changes that need to be in place to enable the parallelization of tests. There are issues with concurrency due to some test and framework design that when run in parallel increase the retry rate of the tests (the tests don't run in parallel when retried). The MR focuses on namespace collision for sandboxes, which can randomly happen when two processes attempt to create the same sandbox simultaneously.
This is only enabled for ephemeral test-on-omnibus environments due to the sandbox limitations we have in live environments.
Before (parallel enabled without the fix)
After (parallel enabled with this fix)
