fix: remove -H:-RunReachabilityHandlersConcurrently (#1892)

* fix: remove -H:-RunReachabilityHandlersConcurrently and legacy ProtobufMessageFeature.java

Author: burkedavison

gax-java/gax-grpc/src/main/java/com/google/api/gax/grpc/nativeimage/ProtobufMessageFeature.java

@@ -11,6 +11,4 @@ Args=--add-opens=java.base/java.time=ALL-UNNAMED \
     io.grpc.netty.shaded.io.netty.handler.ssl,\
     io.grpc.internal.RetriableStream,\
     io.grpc.netty.shaded.io.netty \
-  --features=com.google.api.gax.grpc.nativeimage.ProtobufMessageFeature,\
-  com.google.api.gax.grpc.nativeimage.GrpcNettyFeature \
-  -H:-RunReachabilityHandlersConcurrently
+  --features=com.google.api.gax.grpc.nativeimage.GrpcNettyFeature