Bump BUILDER_IMAGE_REVISION to 5.60.5 for Go 1.26.7 (19.1)

What does this MR do and why?

Bumps BUILDER_IMAGE_REVISION from 5.60.3 to 5.60.5 on 19-1-stable.

Three changes landed on the 5-60-stable builder line between these tags:

Component	5.60.3	5.60.5
Go	1.25.14	1.26.7
Node.js	22.12.0	22.22.3
pnpm	—	11.11.0

Debian 11 image builds also switch to archive.debian.org, since Bullseye is now end of life.

The Go upgrade is the reason for this bump. CNG already runs Go 1.26.7 on the 19.1 line, and the Go upgrade guide requires Omnibus and CNG to build with the same version. It became required when 19-1-stable-ee moved GITLAB_ELASTICSEARCH_INDEXER_VERSION to 5.14.14, whose go.mod declares go 1.26.0.

This is the 19.1 equivalent of !9729 (merged) for 19.2.

Related issues

• Builder Go bump: gitlab-omnibus-builder!519 (merged)
• CNG 19.1 Go bump: gitlab-org/build/CNG!3092 (merged)

Checklist

• Pipeline is green
• ~"workflow::ready for review" set once pipeline passes