[sdk-metrics] Refactor AggregatorStore

[utpilla]

Changes

• Refactor AggregatorStore to reuse the code for taking MetricPoint snapshot

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.52%. Comparing base (6250307) to head (a12caf8).
Report is 164 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5509      +/-   ##
==========================================
+ Coverage   83.38%   85.52%   +2.13%     
==========================================
  Files         297      289       -8     
  Lines       12531    12585      +54     
==========================================
+ Hits        10449    10763     +314     
+ Misses       2082     1822     -260     

Flag	Coverage Δ
unittests	?
unittests-Solution-Experimental	85.29% <100.00%> (?)
unittests-Solution-Stable	85.49% <100.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
src/OpenTelemetry/Metrics/AggregatorStore.cs	85.30% <100.00%> (+4.92%)	⬆️

... and 63 files with indirect coverage changes

[CodeBlanch]

LGTM