Table driven spec in spec/lib/banzai/pipeline/full_pipeline_spec.rb needs shorter spec titles

spec/lib/banzai/pipeline/full_pipeline_spec.rb has has some recent new specs which is causing CI job log to stop logging.

This impedes developers debugging CI failures like in https://gitlab.com/gitlab-org/gitlab/-/jobs/7197685784

In other words, bundle exec rspec -f d spec/lib/banzai/pipeline/full_pipeline_spec.rb:248 should not output very long strings.

One idea is to use ref(:symbol) so that we can refer to the long strings instead.

/cc @digitalmoksha