Temp fix OTel sdk integration

[cijothomas]

Temp fix for #1549

#1511 introduced a dispatcher to send metrics via OTel, which is resetting the internal state of metrics, thereby affecting the perf tests that rely on cumulative nature of these metrics.

This PR modifies the otel part to just do read, without resetting. This should fix the perf tests that was broken last couple of days.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.75%. Comparing base (02c327d) to head (f1624b8).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1552      +/-   ##
==========================================
- Coverage   83.77%   83.75%   -0.03%     
==========================================
  Files         433      433              
  Lines      122633   122633              
==========================================
- Hits       102739   102706      -33     
- Misses      19360    19393      +33     
  Partials      534      534              

Components	Coverage Δ
otap-dataflow	85.03% <100.00%> (-0.05%)	⬇️
query_abstraction	80.61% <ø> (ø)
query_engine	90.31% <ø> (ø)
syslog_cef_receivers	∅ <ø> (∅)
otel-arrow-go	53.50% <ø> (ø)

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