test: Restore wrapped functions in functions_to_trace tests

[alexander-alderman-webb]

Description

Remove the global patch after the span has finished in a finally block.

Based on the flake below

https://github.com/getsentry/sentry-python/actions/runs/30455774959/job/90588843197

with console output

FAILED tests/tracing/test_decorator.py::test_trace_decorator_no_trx - AssertionError: Expected 'mock' to be called once. Called 3 times.
Calls: [call('Cannot create a child span for %s. Please start a Sentry transaction before calling this function.', 'test_decorator.my_example_function'),
 call('[Monitor] health check negative, downsampling with a factor of %d', 10),
 call('Cannot create a child span for %s. Please start a Sentry transaction before calling this function.', 'time.sleep')].

it looks like time.sleep is wrapped with start_span().

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 📊

✅ 98542 passed | ⏭️ 6772 skipped | Total: 105314 | Pass Rate: 93.57% | Execution Time: 355m 32s

📊 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 100.00%. Project has 2499 uncovered lines.
✅ Project coverage is 89.84%. Comparing base (base) to head (head).

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
+ Coverage    89.84%    89.84%        —%
==========================================
  Files          193       193         —
  Lines        24587     24587         —
  Branches      8744      8744         —
==========================================
+ Hits         22088     22088         —
- Misses        2499      2499         —
- Partials      1400      1400         —

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