Got rid of reference to windmill_service_streaming_rpc_batching exper…

…iment (apache#7728)

* There is no need to predicate WindmillServiceStreamingRpcBatchLimitFactory on the windmill_service_streaming_rpc_batching experiment. That experiment is now fully rolled out.

* Fixed argument to streamingEngineEnabled.

runners/google-cloud-dataflow-java/worker/src/main/java/org/apache/beam/runners/dataflow/worker/options/StreamingDataflowWorkerOptions.java

@@ -200,11 +200,7 @@ public static class WindmillServiceStreamingRpcBatchLimitFactory
  public Integer create(PipelineOptions options) {
  StreamingDataflowWorkerOptions streamingOptions =
  options.as(StreamingDataflowWorkerOptions.class);
- if (streamingEngineEnabled(streamingOptions)
- && hasExperiment(streamingOptions, "windmill_service_streaming_rpc_batching")) {
- return Integer.MAX_VALUE;
- }
- return 1;
+ return streamingEngineEnabled(streamingOptions) ? Integer.MAX_VALUE : 1;
  }
  }
 }