chore(core): remove stale blockbuster allowlist for deleted context module

[Mason Daugherty (mdrxy)]

Closes #29530

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Remove a stale BlockBuster allowlist entry in conftest.py referencing aconfig_with_context — the function and its containing module (langchain_core/beta/runnables/context.py) were deleted in fded6c6b1 (Sep 2025, #32850). Spotted by Antonio Mello (@antonio-mello-ai) in #29530.

[codspeed-hq]

Merging this PR will not alter performance

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

✅ 13 untouched benchmarks
⏩ 27 skipped benchmarks¹

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_{Comparing mdrxy/remove-stale-conftest (3c306d0) with master (936b0a6)}

Footnotes

1. 27 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩