Remove redundant reduce in aux_loss logging

[BestJuly]

What does this PR do ?

In previous implementation, reduce across DP is added for the correct aux_loss logging. However, current reduction will cause redundant communication

• For seq_load_balancing_loss and load_balancing_loss, self.tp_cp_group is used (code, code)
• For global_load_balancing_loss, self.tp_dp_cp_group is used (code).

Therefore, related reduction has already been conducted across corresponding parallel group. And we can remove the duplicated one for better perf.

:warning: For major changes (either in lines of code or in its impact), please make sure to first share discuss a design-doc with the team.

Contribution process

flowchart LR
    A[Pre-checks] --> B[PR Tests]
    subgraph Code Review/Approval
        C1[Expert Review] --> C2[Final Review]
    end
    B --> C1
    C2 --> D[Merge]

Pre-checks

• [ ] I want this PR in a versioned release and have added the appropriate Milestone (e.g., Core 0.8)
• [ ] I have added relevant unit tests
• [ ] I have added relevant functional tests
• [ ] I have added proper typing to my code Typing guidelines
• [ ] I have added relevant documentation
• [ ] I have run the autoformatter.sh on my PR

Code review

The following process is enforced via the CODEOWNERS file for changes into megatron/core. For changes outside of megatron/core, it is up to the PR author whether or not to tag the Final Reviewer team.

For MRs into `main` branch

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:warning: Only proceed to the next step once all reviewers have approved, merge-conflict are resolved and the CI is passing.
Final Review might get declined if these requirements are not fulfilled.

(Step 3): Final Review

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(Optional Step 4): Cherry-pick into release branch

If this PR also needs to be merged into core_r* release branches, after this PR has been merged, select Cherry-pick to open a new PR into the release branch.

For MRs into `dev` branch

The proposed review process for `dev` branch is under active discussion.

MRs are mergable after one approval by either [email protected] or [email protected].

Merging your PR

Any member of core-adlr and core-nemo will be able to merge your PR.

[yanring]

Please correctly label this PR

[yanring]

/ok to test fe8e9e26f1e939f96a8240cda7d6841d582458df