Migrate wav2vec2, wav2vec2_conformer, and wav2vec2_bert to standardized output collection decorators

[23atharvaS]

Summary

This PR migrates the wav2vec2 family to the standardized output-capturing interface (@capture_outputs + @can_return_tuple) and includes follow-up compatibility fixes required to make full CI green.

What changed

Core migration (wav2vec2, wav2vec2_conformer, wav2vec2_bert)

• Added _can_record_outputs on:
  • Wav2Vec2PreTrainedModel
  • Wav2Vec2ConformerPreTrainedModel
  • Wav2Vec2BertPreTrainedModel
• Added @capture_outputs on base model forwards:
  • Wav2Vec2Model.forward
  • Wav2Vec2ConformerModel.forward (via modular -> generated)
  • Wav2Vec2BertModel.forward (via modular -> generated)
• Added @can_return_tuple on wrapper forwards (CTC / sequence classification / audio frame classification / xvector / pretraining where applicable).
• Removed manual hidden-state/attention collection loops and legacy output plumbing in migrated paths.
• Updated encoder layer return flow to align with hook-based output capture.
• In conformer/bert modular encoders, ensured only output_attentions is forwarded to self-attention (preventing unrelated kwargs from propagating too deep).

Follow-up compatibility fixes (from CI)

• Restored config-driven forwarding of output_attentions / output_hidden_states in Wav2Vec2Model.forward so config-only output requests are honored.
• Synced the same behavior across related wav2vec2-derived models through modular/generated updates:
  • hubert
  • sew
  • unispeech
  • unispeech_sat
• Fixed SEWEncoderLayer output contract to match encoder expectations.
• Updated UniSpeechForPreTraining / UniSpeechSatForPreTraining to propagate config-driven output flags.
• Updated XcodecModel to accept and thread capture-output kwargs (output_attentions, output_hidden_states) through its semantic backbone call path, fixing test_capture_outputs_decorator.
• Kept attention return compatibility where required by downstream copied implementations.

Files touched (high-level)

• src/transformers/models/wav2vec2/modeling_wav2vec2.py
• src/transformers/models/wav2vec2_conformer/modular_wav2vec2_conformer.py
• src/transformers/models/wav2vec2_conformer/modeling_wav2vec2_conformer.py (regenerated)
• src/transformers/models/wav2vec2_bert/modular_wav2vec2_bert.py
• src/transformers/models/wav2vec2_bert/modeling_wav2vec2_bert.py (regenerated)
• src/transformers/models/hubert/modular_hubert.py
• src/transformers/models/hubert/modeling_hubert.py (regenerated)
• src/transformers/models/sew/modular_sew.py
• src/transformers/models/sew/modeling_sew.py (regenerated)
• src/transformers/models/unispeech/modular_unispeech.py
• src/transformers/models/unispeech/modeling_unispeech.py (regenerated)
• src/transformers/models/unispeech_sat/modular_unispeech_sat.py
• src/transformers/models/unispeech_sat/modeling_unispeech_sat.py (regenerated)
• src/transformers/models/xcodec/modeling_xcodec.py

Validation

Regeneration / consistency

• python utils/check_modular_conversion.py --fix_and_overwrite
• python utils/check_modular_conversion.py
• python utils/check_copies.py --fix_and_overwrite (when needed by CI drift)

Code quality

• python -m ruff check ... on touched files (clean)

Focused output-interface tests

• python -m pytest tests/models/wav2vec2/test_modeling_wav2vec2.py tests/models/wav2vec2_conformer/test_modeling_wav2vec2_conformer.py tests/models/wav2vec2_bert/test_modeling_wav2vec2_bert.py -k "capture_outputs_decorator or attention_outputs or hidden_states_output or model_outputs_equivalence" -q
• Result: pass

Targeted regression reruns for CI failures

• hubert: test_attention_outputs (regular + robust) — pass
• sew: test_attention_outputs — pass
• unispeech: test_attention_outputs (robust) — pass
• unispeech_sat: test_attention_outputs (regular + robust) — pass
• xcodec: test_capture_outputs_decorator — pass
• xcodec: test_model_forward_default_config_values — pass
• glm_ocr: test_generate_with_and_without_position_ids — pass

CI status

• tests_torch and all major CircleCI shards pass.
• Remaining merge blockers are maintainer workflow approval / required review, not code failures.

Notes

• On Windows, test_save_load may fail with a safetensors file-lock issue (os error 1224), which appears environment-specific and unrelated to this migration logic.

[23atharvaS]

This PR is still under testing phase on CI

[23atharvaS]

The PR has passed all of the CircleCI tests

[github-actions]

[For maintainers] Suggested jobs to run (before merge)

run-slow: data2vec, hubert, patchtsmixer, patchtst, sew, sew_d, unispeech, unispeech_sat, wav2vec2, wav2vec2_bert, wav2vec2_conformer, wavlm, xcodec