Fix UnboundLocalError in RT-DETR loss computation (#42224)
* Fix UnboundLocalError in RT-DETR loss computation
Initialize auxiliary_outputs to None before conditional use to prevent
UnboundLocalError when config.auxiliary_loss is False.
Fixes the error:
UnboundLocalError: local variable 'auxiliary_outputs' referenced before assignment
This occurs when auxiliary_loss is disabled but the variable is still
referenced later in the function.
* Update src/transformers/loss/loss_rt_detr.py
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Co-authored-by: Matt <Rocketknight1@users.noreply.github.com>
