feat: Update mainline NGINX to 1.29.3

[DerDreschner]

Proposed changes

This pull request updates the mainline NGINX package to version 1.29.3 and NJS to version 0.9.4.

Checklist

Before creating a PR, run through this checklist and mark each as complete:

• I have read the contributing guidelines
• I have signed the F5 Contributor License Agreement (CLA)
• I have run the update.sh script and ensured all entrypoint/Dockerfile template changes have been applied to the relevant image entrypoint scripts & Dockerfiles
• I have tested that the NGINX Docker unprivileged image builds and runs correctly on all supported architectures on an unprivileged environment (check out the README for more details)
• I have updated any relevant documentation (README.md)

[github-actions]

✅ All required contributors have signed the F5 CLA for this PR. Thank you!
_{Posted by the CLA Assistant Lite bot.}

[DerDreschner]

I have hereby read the F5 CLA and agree to its terms

[DerDreschner]

@alessfg : Could you review and approve this PR?

[alessfg]

Sorry this took so long to review!