Add internal logging for OTLP Exporter tonic client

[utpilla]

Changes

• Add internal logging for OTLP Exporter Tonic client

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

Attention: Patch coverage is 75.00000% with 10 lines in your changes missing coverage. Please review.

Project coverage is 79.2%. Comparing base (e4cba94) to head (12d8c0a).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
opentelemetry-otlp/src/logs.rs	0.0%	3 Missing ⚠️
opentelemetry-otlp/src/exporter/tonic/logs.rs	0.0%	2 Missing ⚠️
opentelemetry-otlp/src/exporter/tonic/metrics.rs	0.0%	2 Missing ⚠️
opentelemetry-otlp/src/exporter/tonic/mod.rs	93.1%	2 Missing ⚠️
opentelemetry-otlp/src/metric.rs	0.0%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #2415     +/-   ##
=======================================
- Coverage   79.2%   79.2%   -0.1%     
=======================================
  Files        122     122             
  Lines      21516   21539     +23     
=======================================
+ Hits       17055   17073     +18     
- Misses      4461    4466      +5     

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[cijothomas]

LGTM!