[2.3.0] Checkmk Werk 16695 created: Just show an error message if redis is not reachable

[//]: # (werk v2) # Just show an error message if redis is not reachable key | value ---------- | --- date | 2024-04-17T06:14:37+00:00 version | 2.3.0b6 class | fix edition | cre component | multisite level | 1 compatible | yes The mega menu search produced a crash report if redis was not reachable. Now only an error message is shown.