I wonder if this is the right fix:
The purpose of the test is "must allow to create a new image if instance supported" and this is a negative assertion for that, so I think the id needs to be changed to an instance that has ":create_image: false", rather than changing the assert on the exception type.
All current 4 instances have :create_image: true so either we need to change one (ensuring that doesn't affect other tests) or add another instance for that.

Or maybe we need both assertions, yours and the one I'm describing above.