Populate the pb::java feature extension to gprc proto plugin (grpc#11885)

Populate the pb::java feature extension to the protoc plugins that require Protobuf Java feature resolution for the  edition.

Author: shaod2

compiler/src/java_plugin/cpp/java_plugin.cpp

@@ -23,6 +23,9 @@
 
 #include "java_generator.h"
 #include <google/protobuf/compiler/code_generator.h>
+#if GOOGLE_PROTOBUF_VERSION >= 5027000
+#include <google/protobuf/compiler/java/java_features.pb.h>
+#endif
 #include <google/protobuf/compiler/plugin.h>
 #include <google/protobuf/descriptor.h>
 #include <google/protobuf/io/zero_copy_stream.h>
@@ -57,6 +60,10 @@ class JavaGrpcGenerator : public protobuf::compiler::CodeGenerator {
   protobuf::Edition GetMaximumEdition() const override {
     return protobuf::Edition::EDITION_2023;
   }
+  std::vector<const protobuf::FieldDescriptor*> GetFeatureExtensions()
+      const override {
+    return {GetExtensionReflection(pb::java)};
+  }
 #else
   uint64_t GetSupportedFeatures() const override {
     return Feature::FEATURE_PROTO3_OPTIONAL;