obs: Deal with packages that never got rebuilt since branching

When branching from e.g. v2022dev1 to v2022dev2 the existing packages get imported without triggering a rebuild. For this reason the build history on v2022dev2 will be empty.

This confuses the build monitor though, so if you trigger a pipeline that does not actually rebuild the package because there are no changes you get a failure.

To avoid that, detect the case of an empty build history and check the latest build status instead.

Task: T6873