Fixed member count for limit checks when publishing sometimes being incorrect (#16667)

no issue

- the members stats service was being used for the total member count
when checking member limits for publishing but the stats service is not
always correct which could result in publishing being blocked
unexpectedly
- switched to using the total count from a `/members/` query which
should always be correct/match other counts within the UI

ghost/admin/app/services/limit.js

@@ -93,9 +93,10 @@ export default class LimitsService extends Service {
     }
 
     async getMembersCount() {
-        const counts = await this.membersStats.fetchCounts();
+        const members = await this.store.query('member', {limit: 'all'});
+        const total = members.meta.pagination.total;
 
-        return counts.total;
+        return total;
     }
 
     async getNewslettersCount() {