Remove threshold for MetricPoint reclaim

[utpilla]

Towards #2360

If a user opts-in for Metric Point reclaim feature, then the SDK would now just start the reclaiming behavior instead of waiting for the usage to reach a threshold. This is done to clean-up metrics faster. The threshold was originally introduced to avoid the perf impact for users who wouldn't require the reclaim feature. Now that MetricPoint reclaim is not enabled by default and is only enabled for users who opt-in for it, we could get rid of the threshold check.

Changes

• Remove threshold for MetricPoint reclaim
• Update MetricPoint reclaim tests to also run with the metric overflow attribute set to true

Merge requirement checklist

• Appropriate CHANGELOG.md files updated for non-trivial changes

[codecov]

Codecov Report

Merging #5087 (885ebcd) into main (eec09c9) will decrease coverage by 0.05%.
The diff coverage is 87.50%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5087      +/-   ##
==========================================
- Coverage   83.38%   83.33%   -0.05%     
==========================================
  Files         296      296              
  Lines       12348    12339       -9     
==========================================
- Hits        10296    10283      -13     
- Misses       2052     2056       +4     

Flag	Coverage Δ
unittests	83.33% <87.50%> (-0.05%)	⬇️

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Files	Coverage Δ
src/OpenTelemetry/Metrics/AggregatorStore.cs	80.00% <87.50%> (-1.61%)	⬇️

... and 7 files with indirect coverage changes