Regression-tracking reference blhc tests are run against the wrong build logs

When the debian_pipeline workflow starts a QA sub-workflow to build reference results, it passes the same value for the package_build_logs parameter as in the normal QA run, namely:

collection: internal@collections
child_type: artifact-or-promise
name__startswith: buildlog-

This is incorrect for a reference run: it needs to look for the build logs associated with the binary packages in qa_suite instead, assuming there are any (there typically won't be for packages we've imported from Debian, but there would be if qa_suite were managed in Debusine).

This is a bit difficult to coordinate, because there's no straightforward way to say "the debian:package-build-logs collection that goes with this debian:suite collection". I think we should change the blhc workflow to accept binary_artifacts as an alternative to package_build_logs, and in that case it would find the actual build logs using relations.