Verify uploads to packagecloud

[amdprophet]

Two packages were missing in packagecloud during the 6.8.2 release despite CI showing that they were successfully uploaded. We should add a step to the CI job to ensure that the packages we uploaded are actually there. We currently have no way of knowing if packages are missing without manually checking package counts against the per-package, per-arch, per-distro, per package type lists defined in cmake/packaging/*/*.