Await shutdown, fix peek/poll bug

Author: jack-berg

sdk-extensions/jaeger-remote-sampler/src/main/java/io/opentelemetry/sdk/extension/trace/jaeger/sampler/JaegerRemoteSampler.java

@@ -185,6 +185,6 @@ public static JaegerRemoteSamplerBuilder builder() {
   public void close() {
     pollFuture.cancel(true);
     pollExecutor.shutdownNow();
-    grpcSender.shutdown();
+    grpcSender.shutdown().join(10, TimeUnit.SECONDS);
   }
 }

sdk-extensions/jaeger-remote-sampler/src/test/java/io/opentelemetry/sdk/extension/trace/jaeger/sampler/JaegerRemoteSamplerTest.java

@@ -103,9 +103,10 @@ public void getSamplingStrategy(
                                     io.opentelemetry.sdk.extension.trace.jaeger.proto.api_v2
                                         .Sampling.SamplingStrategyResponse>
                                 responseObserver) {
-                          ArmeriaStatusException grpcError = grpcErrors.peek();
+                          ArmeriaStatusException grpcError = grpcErrors.poll();
                           if (grpcError != null) {
                             responseObserver.onError(grpcError);
+                            return;
                           }
                           Sampling.SamplingStrategyResponse response = responses.poll();
                           // use default