refactor(storage): split single-shot tests

[coryan]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 81.25000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 96.66%. Comparing base (99c0218) to head (bb4f416).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...age/perform_upload/unbuffered/single_shot_tests.rs	81.25%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3005      +/-   ##
==========================================
- Coverage   96.71%   96.66%   -0.06%     
==========================================
  Files         105      106       +1     
  Lines        4356     4372      +16     
==========================================
+ Hits         4213     4226      +13     
- Misses        143      146       +3     

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