Fix filesize() call on non-existing file

wp-mat.php

@@ -3,7 +3,7 @@
  * Plugin Name: wp-mat
  * Plugin URI: https://git.autistici.org/noblogs/wp-mat
  * Description: Process uploaded files through MAT
- * Version: 0.0.10
+ * Version: 0.0.11
  * Author: Autistici/Inventati
  * Author URI: https://www.autistici.org/
  * License: MIT
@@ -82,7 +82,7 @@ function wp_mat_handle_upload_prefilter($file) {
             "name" => $file['name'],
             "type" => $file['type'],
             "tmp_name" => $file['tmp_name'],
-            "size" => filesize($new_tmp_file),
+            "size" => filesize($file['tmp_name']),
             "error" => 0,
         );
         error_log("wp-mat: successfully cleaned file=".json_encode($new_file));