Reduce memory overhead of `save_to_wav`

scene/resources/audio_stream_wav.cpp

@@ -580,8 +580,7 @@ Error AudioStreamWAV::save_to_wav(const String &p_path) {
 	file->store_32(sub_chunk_2_size); //Subchunk2Size
 
 	// Add data
-	Vector<uint8_t> stream_data = get_data();
-	const uint8_t *read_data = stream_data.ptr();
+	const uint8_t *read_data = data.ptr();
 	switch (format) {
 		case AudioStreamWAV::FORMAT_8_BITS:
 			for (unsigned int i = 0; i < data_bytes; i++) {