Improve GRPC request exception logging

[asifsmohammed]

Is your feature request related to a problem? Please describe.
Right now it's not easy to debug 500 errors in any otel source, if there is an exception which is not an instance of RequestTimeoutException, TimeoutException, SizeOverflowException, BadRequestException, RequestCancelledException we increment the internalServerError metric. With this metric it's not possible to debug the failures without any logging.

data-prepper/data-prepper-plugins/armeria-common/src/main/java/org/opensearch/dataprepper/GrpcRequestExceptionHandler.java

Line 65 in 259fea1

internalServerErrorCounter.increment();

We also return a description with status but looks like the e.getMessage() can be null.

data-prepper/data-prepper-plugins/armeria-common/src/main/java/org/opensearch/dataprepper/GrpcRequestExceptionHandler.java

Line 74 in 259fea1

message = e.getMessage() == null ? status.getCode().name() : e.getMessage();

Describe the solution you'd like
Add a log statement when incrementing the internalServerError metric.
Log should include getCause of throwable if getMessage of the exception is null.

[dlvenable]

I agree with this. With an unknown error like this, we should also log the entire stack trace.

e.g.

log.error("Unexpected exception handling request", e);