Remove Counter/Add benchmark for delta temporality

[fraillt]

Changes

Whether it's Cumulative or Delta temporality, there's no difference for in measurement stage, so I removed redudant benchmarks.

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.4%. Comparing base (ebf1bb6) to head (7152894).
Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2285   +/-   ##
=====================================
  Coverage   79.4%   79.4%           
=====================================
  Files        122     122           
  Lines      20795   20795           
=====================================
  Hits       16514   16514           
  Misses      4281    4281           

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[cijothomas]

Okay with this cleanup, but i think we should still maintain a stress test+benchmark for delta+cumulative. The perf maybe same, but a benchmark is what users can use to validate that they are indeed same.

(There are scenarios where perf maybe diff. for delta and cumulative even in the update path)