Decrease Log Level for "Entity can't be removed from stack, because it does not exist" #6

When an entity is deleted during a test (as part of the test or clean ups), TDL can't delete it.

It then creates an unsettling WARN log Entity can't be removed from stack, because it does not exist.

This should not a WARN, maybe DEBUG because it is not that unusual. If TDL can't delete it, it's most likely already deleted. So nothing to warn about.