services: make BinlogHelper compatible with lite runtime

This commit makes a small change to BinlogHelper to make it compatible with the Protobuf Java Lite runtime.

In the Lite runtime, the `addXBuilder` for repeated fields is not available. Instead, the `addX` method must be used with a manually-constructed Builder.

services/src/main/java/io/grpc/protobuf/services/BinlogHelper.java

@@ -53,6 +53,7 @@
 import io.grpc.binarylog.v1.GrpcLogEntry;
 import io.grpc.binarylog.v1.GrpcLogEntry.EventType;
 import io.grpc.binarylog.v1.Message;
+import io.grpc.binarylog.v1.MetadataEntry;
 import java.net.Inet4Address;
 import java.net.Inet6Address;
 import java.net.InetAddress;
@@ -851,9 +852,8 @@ static MaybeTruncated<io.grpc.binarylog.v1.Metadata.Builder> createMetadataProto
           truncated = true;
           continue;
         }
-        metaBuilder.addEntryBuilder()
-            .setKey(key)
-            .setValue(ByteString.copyFrom(value));
+        metaBuilder.addEntry(
+            MetadataEntry.newBuilder().setKey(key).setValue(ByteString.copyFrom(value)));
         if (!forceInclude) {
           // force included keys do not count towards the size limit
           curBytes = bytesAfterAdd;