Filter by subgroup name before determining if our group has a subgroup

We assumed that the QA sandbox group would continually be wiped and re-created, and thus never have enough subgroups that the one we just created during a new run wouldn't appear on the first page.

But we know what they say about assumptions.

This should resolve the Unable to find css ".new-project-subgroup" errors @bjgopinath was seeing when running against staging.