chore: switch once_cell crate to standard library

[tottoto]

Switches the once_cell crate to the standard library.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 81.81818% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 70.34%. Comparing base (77ce75c) to head (bbbacc9).

Files with missing lines	Patch %	Lines
tests/helpers/mod.rs	66.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2499      +/-   ##
==========================================
+ Coverage   66.95%   70.34%   +3.39%     
==========================================
  Files          64       64              
  Lines       35320    35318       -2     
==========================================
+ Hits        23649    24846    +1197     
+ Misses      11671    10472    -1199     

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