fix: Remove trailing commas causing tuple assignment in response cancellation

[gn00295120]

Fixes #1951

Problem

Trailing commas on lines 434 and 619 in src/agents/realtime/openai_realtime.py create single-element tuples instead of boolean values, breaking the response cancellation logic when interrupt_response=False.

Root Cause

# Buggy (creates tuple):
automatic_response_cancellation_enabled = (..., )  # type: tuple

# Python semantics:
(False,) → tuple, not (False,) → False (truthy)

This causes _cancel_response() to never be called when automatic response cancellation is disabled.

Changes

• Removed trailing commas on lines 434 and 619
• Changes convert tuple assignments to proper boolean expressions

Verification

• Created test demonstrating bug behavior
• Verified bug exists in code (2 occurrences)
• Applied fix and confirmed trailing commas removed
• All 23 realtime tests pass

Impact

• Introduced in: PR feat: #1614 gpt-realtime migration (Realtime API GA) #1646 (commit 9168348, 2025-09-12)
• Severity: CRITICAL - response cancellation completely broken for interrupt_response=False
• Test coverage gap: No existing tests for this scenario

[Copilot]

Pull Request Overview

This PR fixes a critical bug where trailing commas were inadvertently creating single-element tuples instead of boolean values, breaking the response cancellation logic when interrupt_response=False. The trailing commas on lines 434 and 619 caused automatic_response_cancellation_enabled to always evaluate as truthy (a non-empty tuple), preventing _cancel_response() from being called when automatic response cancellation was disabled.

Key Changes:

• Removed trailing commas from two boolean expressions in openai_realtime.py
• Corrected tuple assignments to proper boolean values for automatic_response_cancellation_enabled

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[seratch]

Aha, this is a great catch