fix: align realtime audio event types

[nightcityblade]

• I understand that this repository is auto-generated and my pull request may not be merged

Changes being requested

Fixes #2698.

Updates the non-beta realtime audio response event type literals to match the event names emitted by the API and already used by the beta realtime types:

• response.audio.delta
• response.audio.done
• response.audio_transcript.delta
• response.audio_transcript.done

Adds a small regression test that validates the four realtime audio event models accept those API event names.

Additional context & links

Tests run:

• python3 -m ruff check src/openai/types/realtime/response_audio_delta_event.py src/openai/types/realtime/response_audio_done_event.py src/openai/types/realtime/response_audio_transcript_delta_event.py src/openai/types/realtime/response_audio_transcript_done_event.py tests/test_realtime_types.py
• python3 -m pytest -o addopts='' tests/test_realtime_types.py

[nomiveritas]

"""The event type must be 'response.audio.done'."""
"""The event type must be 'response.audio_transcript.delta'."""
"""The event type must be 'response.audio_transcript.done'."""
We recommend correcting the docstring punctuation by removing the unnecessary commas in phrases such as "The event type, must be ...". The comma is grammatically incorrect and should be omitted.
This should be corrected as part of the change. The punctuation in the affected docstrings is grammatically incorrect and does not meet the expected documentation quality standards

Respectfully Nomiveritas Major Noémi