interop: enable OpenTelemetry tracing support in Java interop client …

[AgraVator]

interop: Enable OpenTelemetry Tracing Support in Java Interop Client and Server

Summary

This PR adds OpenTelemetry Tracing support to the grpc-java interop client and server binaries (TestServiceClient and TestServiceServer), completing Java support for the gRPC OpenTelemetry Tracing Interop Test Plan.

Key Changes

• Dependencies (gradle/libs.versions.toml & interop-testing/build.gradle):
  • Added OpenTelemetry autoconfigure SDK (opentelemetry-sdk-extension-autoconfigure) and OTLP exporter (opentelemetry-exporter-otlp:1.63.0) to interop dependencies.
• Client & Server Instrumentation (TestServiceClient.java & TestServiceServer.java):
  • Added --enable_opentelemetry boolean command-line option.
  • Initialized AutoConfiguredOpenTelemetrySdk with GrpcTraceBinContextPropagator for context propagation compatibility (grpc-trace-bin).
  • Globally registered GrpcOpenTelemetry.
  • Wrapped OpenTelemetry SDK shutdown (openTelemetrySdk.close()) in try-finally blocks to guarantee span flushing upon process exit.
• Code Style & Checkstyle:
  • Adjusted import orders and line length boundaries (<100 characters) to pass checkstyle verification cleanly.

Verification Done

• Java Client $\leftrightarrow$ Java Server: PASSED
• Java Client $\leftrightarrow$ C++ Server: PASSED
• C++ Client $\leftrightarrow$ Java Server: PASSED
• Verified build and checkstyle:

./gradlew :grpc-interop-testing:checkstyleMain
./gradlew :grpc-interop-testing:installDist -x test
python3 test/cpp/interop/run_otel_interop_test.py --client java --server java