fix: Close Jetty h2 streams with RST_STREAM and no error code

Fixes deephaven#5996

grpc-java/grpc-servlet-jakarta/src/main/java/io/grpc/servlet/jakarta/AsyncServletOutputStreamWriter.java

@@ -121,9 +121,9 @@ public boolean isFinestEnabled() {
             transportState.runOnTransportThread(
                     () -> {
                         transportState.complete();
-                        asyncContext.complete();
                         log.fine("call completed");
                     });
+            outputStream.close();
         };
         this.isReady = () -> outputStream.isReady();
     }