Make report-type artifacts available for download

What does this MR do?

This MR allows additional artifact types to be downloaded from pipelines. Future downloadable artifacts can be easily created by adding the file type to Ci::JobArtifact::DOWNLOADABLE_TYPES.

Issue: #23847 (closed)

Screenshots

Report type artifacts can now be downloaded from pipelines:

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.