Introduce the change stream serverless task that will have a mult-tenancy feature enabled. This will help in testing the change stream in the serverless environment.

We will have to be careful when we start running this test in the change_streams_multitenant passthrough - we're disabling change streams in this test, so will need to either make sure we have a unique tenant for this test or that we re-enable change streams at the end of the test, otherwise it'll cause all subsequent tests running on the same fixture to fail.