chore(google-genai): Remove transaction-based tracing

[alexander-alderman-webb]

Description

Remove branches for the static trace lifecycle.
Also remove manual tracing API calls in tests, as the outer transaction is no longer needed.

Closes #7090

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

[sentrivana]

👍🏻 👍🏻 👍🏻

[github-actions]

Codecov Results 📊

✅ 87408 passed | ⏭️ 4112 skipped | Total: 91520 | Pass Rate: 95.51% | Execution Time: 280m 14s

📊 Comparison with Base Branch

Metric	Change
Total Tests	📉 -46186
Passed Tests	📉 -43188
Failed Tests	—
Skipped Tests	📉 -2998

All tests are passing successfully.

✅ Patch coverage is 87.18%. Project has 2250 uncovered lines.
✅ Project coverage is 90.36%. Comparing base (base) to head (head).

Files with missing lines (3)

File	Patch %	Lines
sentry_sdk/integrations/google_genai/init.py	84.44%	⚠️ 7 Missing
sentry_sdk/integrations/google_genai/streaming.py	83.33%	⚠️ 2 Missing
sentry_sdk/integrations/google_genai/utils.py	95.24%	⚠️ 1 Missing and 1 partials

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
+ Coverage    90.24%    90.36%    +0.12%
==========================================
  Files          193       185        -8
  Lines        25724     23336     -2388
  Branches      9504      8564      -940
==========================================
+ Hits         23214     21086     -2128
- Misses        2510      2250      -260
- Partials      1435      1360       -75

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Generated by Codecov Action

[cursor]

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