chore(starlette): Drop transactions

[sentrivana]

Description

Issues

Closes https://linear.app/getsentry/issue/PY-2719/remove-transaction-based-tracing-from-starlette

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

[linear-code]

PY-2719

[github-actions]

Codecov Results 📊

✅ 117105 passed | ⏭️ 5560 skipped | Total: 122665 | Pass Rate: 95.47% | Execution Time: 397m 24s

📊 Comparison with Base Branch

Metric	Change
Total Tests	📈 +17264
Passed Tests	📈 +18183
Failed Tests	—
Skipped Tests	📉 -919

All tests are passing successfully.

✅ Patch coverage is 87.50%. Project has 2255 uncovered lines.
✅ Project coverage is 90.45%. Comparing base (base) to head (head).

Files with missing lines (1)

File	Patch %	Lines
sentry_sdk/integrations/starlette.py	87.50%	⚠️ 1 Missing and 2 partials

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
+ Coverage    89.92%    90.45%    +0.53%
==========================================
  Files          193       185        -8
  Lines        24908     23619     -1289
  Branches      8986      8668      -318
==========================================
+ Hits         22398     21364     -1034
- Misses        2510      2255      -255
- Partials      1430      1372       -58

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