ref(langchain): Revert input transformation

[alexander-alderman-webb]

Description

Revert #5278

Issues

Reminders

• Please add tests to validate your changes, and lint your code using tox -e linters.
• Add GH Issue ID & Linear ID (if applicable)
• PR title should use conventional commit style (feat:, fix:, ref:, meta:)
• For external contributors: CONTRIBUTING.md, Sentry SDK development docs, Discord community

[github-actions]

Semver Impact of This PR

🟢 Patch (bug fixes)

📋 Changelog Preview

This is how your changes will appear in the changelog.
Entries from this PR are highlighted with a left border (blockquote style).

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New Features ✨

• (ci) Cancel in-progress PR workflows on new commit push by joshuarli in #5994
• Send GenAI spans as V2 envelope items by alexander-alderman-webb in #6079

Bug Fixes 🐛

• (google_genai) Redact binary data in inline_data and fix multi-part message extraction by ericapisani in #5977
• (profiler) Stop nulling buffer on teardown by ericapisani in #6075

Internal Changes 🔧

Pydantic Ai

• Revert input truncation by alexander-alderman-webb in #6106
• Remove dead Model.request patch by alexander-alderman-webb in #5956

Other

• (anthropic) Revert input transformation by alexander-alderman-webb in #6108
• (google-genai) Revert input transformation by alexander-alderman-webb in #6105

• (langchain) Revert input transformation by alexander-alderman-webb in #6109

• (litellm) Revert input transformation by alexander-alderman-webb in #6107
• Set explicit base-branch for codecov action by ericapisani in #5992

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_{🤖 This preview updates automatically when you update the PR.}

[github-actions]

Codecov Results 📊

✅ 6 passed | Total: 6 | Pass Rate: 100% | Execution Time: 1.30s

📊 Comparison with Base Branch

Metric	Change
Total Tests	—
Passed Tests	—
Failed Tests	—
Skipped Tests	—

✨ No test changes detected

All tests are passing successfully.

❌ Patch coverage is 0.00%. Project has 16450 uncovered lines.
❌ Project coverage is 21.67%. Comparing base (base) to head (head).

Files with missing lines (2)

File	Patch %	Lines
langchain.py	3.33%	⚠️ 580 Missing
utils.py	21.43%	⚠️ 132 Missing

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
- Coverage    22.14%    21.67%    -0.47%
==========================================
  Files          190       190         —
  Lines        21365     21002      -363
  Branches      7068      7245      +177
==========================================
+ Hits          4730      4552      -178
- Misses       16635     16450      -185
- Partials       383       386        +3

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