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.

⚠️ 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]

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[Victarry]

IIUC, tracker[name]["reduce_group"] should be a ProcessGroup object. How can we get the dp attribute?