Honor sampler environment variable if set

[MrAlias]

No description provided.

[codecov-commenter]

Codecov Report

Merging #724 (050565e) into main (8ff26ac) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #724      +/-   ##
==========================================
+ Coverage   78.87%   78.89%   +0.02%     
==========================================
  Files          55       55              
  Lines        2755     2758       +3     
==========================================
+ Hits         2173     2176       +3     
  Misses        533      533              
  Partials       49       49              

Flag	Coverage Δ
Linux	78.89% <100.00%> (+0.02%)	⬆️
macOS	75.12% <100.00%> (?)

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Impacted Files	Coverage Δ
distro/otel.go	65.57% <100.00%> (+1.78%)	⬆️

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[pellared]

How about updating the changelog?