test(flask): Remove transactions

[sentrivana]

While the Flask integration itself doesn't differentiate if span streaming is enabled or not, the tests do.

[github-actions]

Codecov Results 📊

✅ 107904 passed | ⏭️ 5338 skipped | Total: 113242 | Pass Rate: 95.29% | Execution Time: 357m 48s

📊 Comparison with Base Branch

Metric	Change
Total Tests	📈 +7841
Passed Tests	📈 +8982
Failed Tests	—
Skipped Tests	📉 -1141

All tests are passing successfully.

✅ Patch coverage is 100.00%. Project has 2248 uncovered lines.
✅ Project coverage is 90.52%. Comparing base (base) to head (head).

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
+ Coverage    90.30%    90.52%    +0.22%
==========================================
  Files          193       185        -8
  Lines        25601     23705     -1896
  Branches      9436      8734      -702
==========================================
+ Hits         23116     21457     -1659
- Misses        2485      2248      -237
- Partials      1435      1365       -70

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