Enable pipeline_report_api flag by default

What does this MR do?

Enables the pipeline_report_api flag by default. It enables the functionality added in !15682 (merged).

This is part of #13496 (closed).

This should be merged at the same time as the docs MR, although the order doesn't matter.

Note

This is currently based on !15682 (merged), and should be rebased once that is merged. Then this can be merged.

Screenshots

See !15682 (merged).

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• [-] Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Performance and Testing