Address code review feedback: optimize logger instantiation and null handling

- Move logger to static final class member for efficiency
- Add null checks for getDescription() to preserve fallback values
- All tests still pass successfully

Co-authored-by: ahmedmuhsin <36454324+ahmedmuhsin@users.noreply.github.com>

Author: Copilot

src/main/java/com/microsoft/azure/functions/worker/JavaWorkerClient.java

@@ -20,6 +20,8 @@
  * Thread-Safety: Single thread.
  */
 public class JavaWorkerClient implements AutoCloseable {
+    private static final Logger logger = Logger.getLogger(JavaWorkerClient.class.getName());
+    
     public JavaWorkerClient(IApplication app) {
         WorkerLogManager.initialize(this, app.logToConsole());
         ManagedChannelBuilder<?> chanBuilder = ManagedChannelBuilder.forAddress(app.getHost(), app.getPort()).usePlaintext();
@@ -101,18 +103,23 @@ public void onNext(StreamingMessage message) {
 
         @Override
         public void onError(Throwable t) {
-            Logger logger = Logger.getLogger(JavaWorkerClient.class.getName());
             String statusCode = "Unknown";
             String statusDescription = t.getMessage();
 
             if (t instanceof io.grpc.StatusRuntimeException) {
                 io.grpc.StatusRuntimeException sre = (io.grpc.StatusRuntimeException) t;
                 statusCode = sre.getStatus().getCode().name();
-                statusDescription = sre.getStatus().getDescription();
+                String description = sre.getStatus().getDescription();
+                if (description != null) {
+                    statusDescription = description;
+                }
             } else if (t instanceof io.grpc.StatusException) {
                 io.grpc.StatusException se = (io.grpc.StatusException) t;
                 statusCode = se.getStatus().getCode().name();
-                statusDescription = se.getStatus().getDescription();
+                String description = se.getStatus().getDescription();
+                if (description != null) {
+                    statusDescription = description;
+                }
             }
 
             logger.severe(String.format(