[2.3.0] Checkmk Werk 16209 created: downtimes: Fix performance issues when creating downtimes

[//]: # (werk v2) # downtimes: Fix performance issues when creating downtimes key | value ---------- | --- date | 2023-12-20T08:56:08+00:00 version | 2.3.0b1 class | fix edition | cre component | rest-api level | 1 compatible | yes This Werk fixes a performance issue that occurred when creating downtimes for services in a distributed monitoring environment.