Log maximum size of upload with "entity is too large" error

When we report a 413 entity is too large error, we should log what the maximum size to be able to determine what limit we hit. We had to look at the Rails console output to determine this for https://gitlab.com/gitlab-org/gitlab-runner/-/jobs/880982067:

[ gprd ] production> proj = Project.find_by_full_path("gitlab-org/gitlab-runner")
=> #<Project id:250833 gitlab-org/gitlab-runner>>
[ gprd ] production> proj.closest_setting(:max_artifacts_size)
=> 2000
[ gprd ] production> Ci::JobArtifact.max_artifact_size(type: 'archive', project: proj)
=> 2097152000