Adjusted email jobs registration to check for emails newer than 30 days

no issue

- if emails are older than 30 days we wouldn't be able to fetch any analytics for them and if a site used emails in the past but is no longer using them it doesn't make sense to keep potentially expensive background worker threads spinning up

core/server/services/email-analytics/jobs/index.js

@@ -14,7 +14,10 @@ module.exports = {
         ) {
             // don't register email analytics job if we have no emails,
             // processer usage from many sites spinning up threads can be high
-            const emailCount = await models.Email.count();
+            const emailCount = await models.Email
+                .where('status', 'submitted')
+                .where('created_at', '>', moment.utc().subtract(30, 'days').toDate())
+                .count();
 
             if (emailCount > 0) {
                 // use a random seconds value to avoid spikes to external APIs on the minute