Core 10.1 follow up: check and update event handler to avoid css/js

Problem/Motivation

The Issue 🐛 Incompatibility with antibot module Closed: works as designed showed a problem which can bring several problems and should be checked and fixed if needed.

Because I currently have to solve customer problem with css/js aggregation I took a deeper look inside the new strategy of the core with the routes 'system.css_asset' and system.js_asset ("core/modules/system/src/Routing/AssetRoutes.php"). The core is now acting a little bit like the boost module is doing. It first tries to deliver existing files, generates if needed, and finally dumps them to file system. On a first step we should just exclude this routes from caching because the core already creates static files. Maybe it makes sense to include them with some configurable logic in future.

See also [Core 10.1 Change record]( https://www.drupal.org/node/2888767 → )