MDL-77105 mod_url: Declare filtericon custom data

* Set a custom data `filtericon` when the icon being rendered for the
URL resource is not equal to the default plugin icon.

mod/url/lib.php

@@ -245,6 +245,8 @@ function url_get_coursemodule_info($coursemodule) {
     }
 
     $info->customdata['display'] = $display;
+    // The icon will be filtered if it will be the default module icon.
+    $info->customdata['filtericon'] = empty($info->icon);
 
     return $info;
 }