Fix the query to return the count of events

Left join was causing events to counted multiple times (once per participation). Using DISTINCT fixes this.

src/Bundle/ChillEventBundle/Export/Export/CountEvents.php

@@ -94,7 +94,7 @@ readonly class CountEvents implements ExportInterface, GroupedExportInterface
             ->leftJoin('event.participations', 'epart')
             ->leftJoin('epart.person', 'person');
 
-        $qb->select('COUNT(event.id) as export_count_event');
+        $qb->select('COUNT(DISTINCT event.id) as export_count_event');
 
         if ($this->filterStatsByCenters) {
             $qb