refactor: InMemoryLogsExporter non plural

[pitoniak32]

related to comments:

• Refactor/metric exporters non plural #2255 (comment)
• feat: replace OtlpPipeline with exporter builders #2221 (comment)

Changes

De-pluralize Log Exporter types:

• InMemoryLogsExporter -> InMemoryLogExporter
• Fix rename on LogExporter Debug impl.

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 93.10345% with 2 lines in your changes missing coverage. Please review.

Project coverage is 79.4%. Comparing base (17f4627) to head (973a8bd).

Files with missing lines	Patch %	Lines
opentelemetry-sdk/src/logs/log_processor.rs	92.3%	1 Missing ⚠️
opentelemetry-stdout/src/logs/exporter.rs	0.0%	1 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2258   +/-   ##
=====================================
  Coverage   79.4%   79.4%           
=====================================
  Files        121     121           
  Lines      20962   20962           
=====================================
+ Hits       16654   16656    +2     
+ Misses      4308    4306    -2     

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[lalitb]

Thanks. I believe it would be better to update the otel-sdk changelog even if the exporter is meant for testing, as done for metrics in #2255.