7.0.2 test suites failing

In https://github.com/couchbaselabs/observability/commit/0c9e8ce8f98c9f9b4735834b38c1f58850ad0793 we added a Docker image of "CBS + Exporter" This has a build arg called couchbase_server_image (with a default of couchbase/server:6.6.3) to override the base image to build off of.

Unfortunately, in our test suites we pass the build arg COUCHBASE_SERVER_IMAGE - so the image to use defaults to 6.6.3, which breaks 7.x tests as they use CBS user roles that aren't present in 6.6.3.