Make checkAccess method fail access check, if there is a script execution problem

If the method is missing, allow access. If the method execution fails (for example a syntax error in the method), let the access check also fail.

https://gitlab.kit.edu/kit/reg-app/regapp/-/blob/main/regapp-drools/src/main/java/edu/kit/scc/webreg/drools/impl/KnowledgeSessionSingleton.java#L212