[onecollector] Add LoggerProviderBuilder registration extension

[CodeBlanch]

Changes

• Adds LoggerProviderBuilder.AddOneCollectorExporter to support LoggerProviderBuilder patterns being introduced in OTel 1.9.0.

Checklist

• Appropriate CHANGELOG.md updated for non-trivial changes
• Unit tests updated
• Changes in public API reviewed

[codecov]

Codecov Report

Attention: Patch coverage is 94.73684% with 5 lines in your changes missing coverage. Please review.

Project coverage is 91.51%. Comparing base (71655ce) to head (f1f4a4c).
Report is 294 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1876       +/-   ##
===========================================
+ Coverage   73.91%   91.51%   +17.59%     
===========================================
  Files         267       26      -241     
  Lines        9615     1013     -8602     
===========================================
- Hits         7107      927     -6180     
+ Misses       2508       86     -2422     

Flag	Coverage Δ
unittests-Exporter.OneCollector	91.51% <94.73%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
...rialization/LogRecordCommonSchemaJsonSerializer.cs	98.34% <ø> (-0.83%)	⬇️
...ctor/Logs/OneCollectorLogExportProcessorBuilder.cs	96.73% <100.00%> (+28.99%)	⬆️
...neCollectorOpenTelemetryLoggerOptionsExtensions.cs	76.47% <100.00%> (-1.31%)	⬇️
...eCollector/OneCollectorExporterTransportOptions.cs	76.47% <100.00%> (+5.04%)	⬆️
...ogs/OneCollectorLoggerProviderBuilderExtensions.cs	81.48% <81.48%> (ø)

... and 253 files with indirect coverage changes