Observability improvements for cloud native build logs

Description

We have recently managed to enable Cloud Native Build Logs feature in every project on Gitlab.com - 100% feature rollout.

The feature works well there, but there is still some room for improvements:

1. Improve observability to differentiate between mutated and malformed build log ➡ gitlab-runner!2521 (merged)
2. Improve trace range violation logging ➡ !46256 (merged)