Performance fix for address_merge, when there are a log of echomails to move to the new address

app/Http/Controllers/SystemController.php

@@ -346,7 +346,11 @@ class SystemController extends Controller
 				->join('echomail_seenby',['echomail_seenby.echomail_id'=>'echomails.id'])
 				->whereIn('address_id',[$request->src])
 				->distinct()
-				->with(['seenby:id'])
+				->with(['seenby'=>function($query) use ($request) {
+					return $query
+						->select('id')
+						->whereIn('address_id',[$request->src,$request->dst]);
+				}])
 				->get()
 				->filter(function($item) use ($request) {
 					return $item->seenby->contains($request->dst) && $item->seenby->contains($request->src);