[2.2.0] Checkmk Werk 16366 created: rule: Fix crash on rule creation via REST API without conditions or properties

Title: rule: Fix crash on rule creation via REST API without conditions or properties Class: fix Compatible: compat Component: rest-api Date: 1707462364 Edition: cre Level: 1 Version: 2.2.0p22 Before this Werk, an status code 500 Internal Server Error was returned when creating a rule without conditions or properties. This Werk fixes it and now it is possible to create a rule in such conditions.