Use cached size when passing artifacts to Runner

What does this MR do?

It seems that during /jobs/request when we fetch a list of dependent artifacts we perform Object Storage call to get an file size.

We can avoid that using :cached_size that is stored as part of a model.

What are the relevant issue numbers?

Related to https://gitlab.com/gitlab-org/gitlab-ce/issues/53843

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides