Detect broken master if only doc-only MRs have successful pipeline

This incident started two days ago (2025-03-26 16:42 UTC), but release managers didn't realize that because since this incident didn't impact the doc-only MRs, their pipelines still succeeded, thus new commits were still picked into the auto-deploy packages. This leads to two consequences:

• Buggy commits may be overlooked
• We didn't realize broken master

This ticket was created from INC-356 and was automatically exported by incident.io 🔥