fix: Allow Histograms with no buckets

[cijothomas]

Fixes #2354

[codecov]

Codecov Report

Attention: Patch coverage is 70.68966% with 17 lines in your changes missing coverage. Please review.

Project coverage is 81.3%. Comparing base (7f8adcc) to head (7e0f618).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
opentelemetry-stdout/src/metrics/exporter.rs	0.0%	14 Missing ⚠️
opentelemetry-sdk/src/metrics/mod.rs	92.1%	3 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2948   +/-   ##
=====================================
  Coverage   81.3%   81.3%           
=====================================
  Files        126     126           
  Lines      24251   24294   +43     
=====================================
+ Hits       19736   19771   +35     
- Misses      4515    4523    +8     

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