Align CompactConsoleLogRecordExporter with OTLP backend schema

[Miqueasher]

Summary

• Align CompactConsoleLogRecordExporter JSON output with CloudWatch OTLP
  backend format (field names, types, structure)
• Fix customizeLogsExporter to support OTEL_LOGS_EXPORTER=otlp,console
  — previously only console (exact match) was recognized
• Fix SigV4 config validation to accept comma-separated exporter lists
• Fix unsafe cast that crashed the OTel agent when both OTLP and console
  exporters were enabled simultaneously
• Add exportPath:"console" field to enable independent validation of
  console vs OTLP export paths

Bug Fixes

1. SigV4 never enabled with otlp,console: isSigv4ValidConfig() checked
   exporter.equals("otlp") which fails for "otlp,console". Changed to
   .contains("otlp").

2. OTel agent crash with dual exporters: customizeLogsExporter() blindly
   cast every exporter to OtlpHttpLogRecordExporter. When called with
   SystemOutLogRecordExporter , it threw
   ClassCastException → IllegalStateException, crashing the entire agent.
   Added instanceof check before cast.

3. Console exporter not wired in with otlp,console: Previously checked
   logsExporterConfig.equals("console"). Now checks the exporter's class name
   (SystemOutLogRecordExporter) to correctly identify and replace it regardless
   of the config string.

Test plan

• Unit tests updated and passing (all awsagentprovider tests pass)
• E2E validated locally: built layer from source, deployed Lambda via
  Terraform, verified console JSON in CloudWatch, verified OTLP logs in
  otlp-logs stream, ran validator — PASSED
• Depends on test framework PR being merged first for CI validation

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.