test(pydantic-ai): Use FunctionModel for testing output data transformations

[alexander-alderman-webb]

Description

Removing some mocks by using FunctionModel() with pydantic-ai types.

Removed both test_model_response_without_parts() and test_set_output_data_without_prompts(), since they don't assert anything meaningful.

Issues

Reminders

• Please add tests to validate your changes, and lint your code using uv run ruff.
• 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]

Codecov Results 📊

✅ 96984 passed | ⏭️ 6239 skipped | Total: 103223 | Pass Rate: 93.96% | Execution Time: 349m 30s

📊 Comparison with Base Branch

Metric	Change
Total Tests	📈 +10
Passed Tests	📈 +10
Failed Tests	—
Skipped Tests	—

All tests are passing successfully.

✅ Patch coverage is 100.00%. Project has 2504 uncovered lines.
❌ Project coverage is 89.91%. Comparing base (base) to head (head).

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
- Coverage    89.94%    89.91%    -0.03%
==========================================
  Files          193       193         —
  Lines        24828     24828         —
  Branches      8930      8930         —
==========================================
+ Hits         22331     22324        -7
- Misses        2497      2504        +7
- Partials      1414      1415        +1

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