Don't use ExtensionRegistry.getGeneratedRegistry() when parsing protos in our code. Needed to ease the proto2 migration to newer version.

PiperOrigin-RevId: 751189880
Change-Id: I3e40bdceebc1e0589de3af32af0e0dbee1efd6ed

Author: ludoch

lib/tools_api/src/main/protobuf/runtime_config.proto

@@ -22,7 +22,6 @@ syntax = "proto2";
 
 package cloud_trace;
 
-import "label_options.proto";
 import "span_kind.proto";
 
 option java_package = "com.google.apphosting.base.protos";

protobuf/label_options.proto

@@ -151,7 +151,7 @@ public RemoteApiPb.TransactionRequest makeCommitRequest() {
         Message.Builder newKey = result.getDeletesBuilder().addKeyBuilder();
         boolean parsed = true;
         try {
-          newKey.mergeFrom(entry.getKey(), ExtensionRegistry.getGeneratedRegistry());
+          newKey.mergeFrom(entry.getKey(), ExtensionRegistry.getEmptyRegistry());
         } catch (InvalidProtocolBufferException e) {
           parsed = false;
         }
@@ -170,7 +170,7 @@ private static RemoteApiPb.TransactionRequest.Precondition makeEntityNotFoundPre
     OnestoreEntity.Reference.Builder ref = OnestoreEntity.Reference.newBuilder();
     boolean parsed = true;
     try {
-      ref.mergeFrom(key, ExtensionRegistry.getGeneratedRegistry());
+      ref.mergeFrom(key, ExtensionRegistry.getEmptyRegistry());
     } catch (InvalidProtocolBufferException e) {
       parsed = false;
     }