Move the RubyMessage.java JSON "include defaults" to use alwaysPrintF…

…ieldsWithNoPresence.

This is no different on proto3 but treats proto2-optional differently (to make it consistent with proto3-optional).

PiperOrigin-RevId: 604354927

ruby/src/main/java/com/google/protobuf/jruby/RubyMessage.java

@@ -700,7 +700,7 @@ public static IRubyObject encodeJson(
           options.fastARef(runtime.newSymbol("format_enums_as_integers"));
 
       if (emitDefaults != null && emitDefaults.isTrue()) {
-        printer = printer.includingDefaultValueFields();
+        printer = printer.alwaysPrintFieldsWithNoPresence();
       }
 
       if (preserveNames != null && preserveNames.isTrue()) {