[nvnflinger] Add case for DefaultDataSpace (#3956)

Amaterasu from Discord asked about why nvnWindowGetNumActiveTextures returns 0 - after researching the console output it was asking for `DefaultDataSpace` (enum val 12) after some tests with the mod and debugging the console, this is my one-liner solution.

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3956
Reviewed-by: Lizzie <lizzie@eden-emu.dev>
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>

src/core/hle/service/nvnflinger/buffer_queue_producer.cpp

@@ -612,6 +612,9 @@ Status BufferQueueProducer::Query(NativeWindow what, s32* out_value) {
     case NativeWindow::ConsumerUsageBits:
         value = core->consumer_usage_bit;
         break;
+    case NativeWindow::DefaultDataSpace:
+        value = core->GetMaxBufferCountLocked(false);
+        break;
     default:
         ASSERT(false);
         return Status::BadValue;