chore(beep boop 🤖): Bump `MCORE_TAG=2da43ef...` (2024-12-27)
🚀 PR to bump `NVIDIA/Megatron-LM` in `Dockerfile.ci` to `MCORE_TAG=2da43ef4c1b9e76f03b7567360cf7390e877f1b6`.  

📝 Please remember the following to-do's before merge: 
- [ ] Verify the presubmit CI  

🙏 Please merge this PR only if the CI workflow completed successfully.