Fix gradebook table - refs BT#12515

Fix Scrutinizer WRONG Auto-Fix a4d28af0e4 (diff-ba0a0a766c4d518018b2c8bdefd11646)

main/gradebook/lib/fe/gradebooktable.class.php

@@ -254,11 +254,11 @@ class GradebookTable extends SortableTable
         }
 
         // Categories.
-        if (!empty($data_array)) {
+        if (!empty($data_array))
                 foreach ($data_array as $data) {
             // list of items inside the gradebook (exercises, lps, forums, etc)
             $row  = array();
-        }
+
             /** @var AbstractLink $item */
             $item = $mainCategory = $data[0];