chore(beep boop 🤖): Bump `MCORE_TAG=c76410a...` (2025-01-13)
🚀 PR to bump `NVIDIA/Megatron-LM` in `Dockerfile.ci` to `MCORE_TAG=c76410adec0eb1f81544344fcc2c404166e9913d`.  

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

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