[Fix] Restore ES metrics

[AnmolxSingh]

Which problem is this PR solving?

• Resolves [Bug]: ES store metrics got lost #6891

Description of the changes

• Reintroduced metrics which were lost during [ES] Separate the CoreSpanWriter from SpanWriter #6883

How was this change tested?

• Ran writer tests

Checklist

• I have read https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
• I have signed all commits
• I have added unit tests for the new functionality
• I have run lint and test steps successfully
  • for jaeger: make lint test
  • for jaeger-ui: npm run lint and npm run test

[codecov]

Codecov Report

Attention: Patch coverage is 95.34884% with 2 lines in your changes missing coverage. Please review.

Project coverage is 96.20%. Comparing base (1e691d5) to head (6b6d8ea).
Report is 24 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/storage/elasticsearch/config/config.go	95.12%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7006      +/-   ##
==========================================
+ Coverage   96.12%   96.20%   +0.07%     
==========================================
  Files         357      358       +1     
  Lines       21570    21596      +26     
==========================================
+ Hits        20735    20777      +42     
+ Misses        629      613      -16     
  Partials      206      206              

Flag	Coverage Δ
badger_v1	9.90% <0.00%> (-0.03%)	⬇️
badger_v2	2.05% <0.00%> (-0.01%)	⬇️
cassandra-4.x-v1-manual	14.89% <0.00%> (-0.04%)	⬇️
cassandra-4.x-v2-auto	2.04% <0.00%> (-0.01%)	⬇️
cassandra-4.x-v2-manual	2.04% <0.00%> (-0.01%)	⬇️
cassandra-5.x-v1-manual	14.89% <0.00%> (-0.04%)	⬇️
cassandra-5.x-v2-auto	2.04% <0.00%> (-0.01%)	⬇️
cassandra-5.x-v2-manual	2.04% <0.00%> (-0.01%)	⬇️
elasticsearch-6.x-v1	20.23% <53.48%> (+0.03%)	⬆️
elasticsearch-7.x-v1	20.31% <53.48%> (+0.03%)	⬆️
elasticsearch-8.x-v1	20.49% <53.48%> (+0.03%)	⬆️
elasticsearch-8.x-v2	2.05% <0.00%> (-0.01%)	⬇️
grpc_v1	11.44% <0.00%> (-0.03%)	⬇️
grpc_v2	2.05% <0.00%> (-0.01%)	⬇️
kafka-3.x-v1	10.17% <0.00%> (-0.03%)	⬇️
kafka-3.x-v2	2.05% <0.00%> (-0.01%)	⬇️
memory_v2	2.05% <0.00%> (-0.01%)	⬇️
opensearch-1.x-v1	20.36% <53.48%> (+0.03%)	⬆️
opensearch-2.x-v1	20.36% <53.48%> (+0.03%)	⬆️
opensearch-2.x-v2	2.05% <0.00%> (-0.01%)	⬇️
query	2.05% <0.00%> (-0.01%)	⬇️
tailsampling-processor	0.55% <0.00%> (-0.01%)	⬇️
unittests	95.02% <83.72%> (+0.08%)	⬆️

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[AnmolxSingh]

@yurishkuro I just wanted to know about my direction at moment.

[yurishkuro]

I don't see any unit tests validating that the expected metrics are being emitted

[AnmolxSingh]

I don't see any unit tests validating that the expected metrics are being emitted

While writing the unit tests for emitted metrices I was thinking of simulating the .After() callback.
Is this approach correct?

[yurishkuro]

I was thinking of simulating the

you can move the code of the callback into a top level function which you can call directly from the test