fix otel crate api breakage

[paultag]

I'm not convinced the otel stuff is right, the API here changed a ton between 0.26 and 0.27. I'm going to read more carefully but this was what I could infer off READMEs.

There's no upgrading guide.

[codecov]

Codecov Report

Attention: Patch coverage is 16.66667% with 5 lines in your changes missing coverage. Please review.

Project coverage is 24.63%. Comparing base (0ead022) to head (8d3b132).
Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
src/bin/machine-api/main.rs	0.00%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #186      +/-   ##
==========================================
+ Coverage   24.60%   24.63%   +0.02%     
==========================================
  Files          51       51              
  Lines        3280     3272       -8     
==========================================
- Hits          807      806       -1     
+ Misses       2473     2466       -7     

Flag	Coverage Δ
unittests	24.63% <16.66%> (+0.02%)	⬆️

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