18-6 Stable Bump Container Registry to v4.31.1-gitlab

What does this MR do and why?

4.31.1 (2025-11-21)

Bug Fixes

• registry: disable REGISTRY_FF_ENFORCE_LOCKFILES by default (06e1c57)

Temporary fix for fix: gracefully handle inconsistent lockfile st... (container-registry#1776) • Hayley Swimelar • 18.8 • At risk

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• This MR is backporting a bug fix, documentation update, or spec fix, previously merged in the default branch.
• The original MR has been deployed to GitLab.com (not applicable for documentation or spec changes).
• This MR has a severity label assigned (if applicable).

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