[2.3.0] Checkmk Werk 16580 created: Dashboard: Fix event statistics not displaying information if no events found

[//]: # (werk v2) # Dashboard: Fix event statistics not displaying information if no events found key | value ---------- | --- date | 2024-03-20T10:34:20+00:00 version | 2.3.0b5 class | fix edition | cre component | multisite level | 1 compatible | yes Prior to this Werk, if no events were found, the event statistics dashlet was drawn empty. This Werk corrects that behaviour and if no events are found, the graph should show with a count of zero.