fix(storage): correct resumable uploads threshold

[coryan]

Resumable uploads are enabled for sizes greater than or equal to
the threshold. If we want to guarantee single-shot uploads we need to
make the threshold larger than the size.

Motivated by #2824

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.17%. Comparing base (f5ffd2b) to head (6839bd1).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2938   +/-   ##
=======================================
  Coverage   96.17%   96.17%           
=======================================
  Files         105      105           
  Lines        4394     4394           
=======================================
  Hits         4226     4226           
  Misses        168      168           

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