Make addition of config object specific to gltf files

Signed-off-by: Justin Georgi <justin.georgi@gmail.com>

includes/GlModelHooks.php

@@ -130,6 +130,8 @@ class GlModelHooks {
      * @param SpecialUpload $uploadFormObj current SpecialUpload object
      */
     public static function onUploadFormBeforeProcessing( $uploadFormObj ) {
+        preg_match('/(glb|gltf)$/', $uploadFormObj->mUpload->getTitle(), $isGltf);
+        if ($isGltf) {
             $uploadFormObj->mComment .= <<<CONF
             
             <mvconfig>
@@ -144,6 +146,7 @@ class GlModelHooks {
             }
             </mvconfig>
             CONF;
+        }
 
         return true;
     }