Optimising count query : Added option param to skip distinct from count query for members events API (#20700)

Ref:
https://linear.app/tryghost/issue/ENG-1470/improve-the-performance-of-the-membersevents-aggregated-click-event

ghost/members-api/lib/repositories/EventRepository.js

@@ -507,6 +507,7 @@ module.exports = class EventRepository {
             ...options,
             withRelated: ['member'],
             filter: 'custom:true',
+            useBasicCount: true,
             mongoTransformer: chainTransformers(
                 // First set the filter manually
                 replaceCustomFilterTransformer(filter),