[admin] Use OTEL helper instead of tlscfg

[chahatsagarmain]

Which problem is this PR solving?

• Part of [Bug]: race condition when reloading TLS certificates #4316

Description of the changes

How was this change tested?

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: yarn lint and yarn test

[codecov]

Codecov Report

Attention: Patch coverage is 94.87179% with 2 lines in your changes missing coverage. Please review.

Project coverage is 96.04%. Comparing base (4162f57) to head (a8af5d7).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
cmd/internal/flags/admin.go	94.87%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #6319       +/-   ##
===========================================
+ Coverage   49.01%   96.04%   +47.02%     
===========================================
  Files         182      357      +175     
  Lines       11212    20467     +9255     
===========================================
+ Hits         5496    19657    +14161     
+ Misses       5269      619     -4650     
+ Partials      447      191      -256     

Flag	Coverage Δ
badger_v1	8.76% <ø> (ø)
badger_v2	1.60% <ø> (ø)
cassandra-4.x-v1-manual	14.73% <ø> (ø)
cassandra-4.x-v2-auto	1.55% <ø> (ø)
cassandra-4.x-v2-manual	1.55% <ø> (ø)
cassandra-5.x-v1-manual	14.73% <ø> (ø)
cassandra-5.x-v2-auto	1.55% <ø> (ø)
cassandra-5.x-v2-manual	1.55% <ø> (ø)
elasticsearch-6.x-v1	18.35% <ø> (-0.01%)	⬇️
elasticsearch-7.x-v1	18.44% <ø> (+<0.01%)	⬆️
elasticsearch-8.x-v1	18.60% <ø> (ø)
elasticsearch-8.x-v2	1.60% <ø> (ø)
grpc_v1	10.25% <ø> (ø)
grpc_v2	7.79% <ø> (ø)
kafka-v1	9.16% <ø> (ø)
kafka-v2	1.60% <ø> (ø)
memory_v2	1.60% <ø> (+<0.01%)	⬆️
opensearch-1.x-v1	18.48% <ø> (ø)
opensearch-2.x-v1	18.47% <ø> (ø)
opensearch-2.x-v2	1.60% <ø> (ø)
tailsampling-processor	0.45% <ø> (ø)
unittests	94.95% <94.87%> (?)

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