Fix averaging for MoE z-loss metric tracking

[Marks101]

What does this PR do ?

At the moment there is no aggregation of MoE z-loss for metric tracking between ranks. The call to save_to_aux_losses_tracker() specifies neither reduce_group nor avg_group. In our understanding this metric should be averaged among tp, cp and dp groups.

Before #2095 all metric actually have been averaged per default along tp and cp groups, but even then there was no aggregation for tp for MoE z-loss.

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[dimapihtar]

/ok to test a0177b6

[ilml]

/ok to test 516e6f9