ref(pydantic-ai): Replace individual hooks with hooks.on.model_request

[alexander-alderman-webb]

Description

Noticed that we can simplify while working on the major.

Use hooks.on.model_request to replace all of hooks.on.before_model_request, hooks.on.model_request_error and hooks.on.after_model_request.

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 📊

✅ 121930 passed | ⏭️ 6762 skipped | Total: 128692 | Pass Rate: 94.75% | Execution Time: 415m 5s

📊 Comparison with Base Branch

Metric	Change
Total Tests	—
Passed Tests	📈 +1
Failed Tests	📉 -1
Skipped Tests	—

➖ Removed Tests (1)

View removed tests

• test_continuous_profiler_auto_start_and_stop_sampled[experiment-thread]
  • File: tests.profiler.test_continuous_profiler

All tests are passing successfully.

✅ Patch coverage is 100.00%. Project has 2484 uncovered lines.
✅ Project coverage is 90.29%. Comparing base (base) to head (head).

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
+ Coverage    90.27%    90.29%    +0.02%
==========================================
  Files          193       193         —
  Lines        25649     25580       -69
  Branches      9454      9418       -36
==========================================
+ Hits         23153     23096       -57
- Misses        2496      2484       -12
- Partials      1445      1428       -17

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