fix(events): point Messaging settings at suite defaults, not API keys

Mirror Care: suite platform keys count as ready for attendee email/SMS;
Account Messaging is primary, product Bird/SMS keys are advanced.
SmsService now prefers channel=suite before customer API keys.

app/Http/Controllers/Events/AttendeeController.php

@@ -154,6 +154,9 @@ class AttendeeController extends Controller
             'programme' => $programme,
             'commsModes' => $commsModes,
             'defaultCommsMode' => $commsModes[0] ?? EventCommsService::MODE_PROGRAMME,
+            'messagingSettingsUrl' => function_exists('ladill_account_url')
+                ? ladill_account_url('/account/settings/messaging')
+                : (string) config('smtp.messaging_settings_url', 'https://account.ladill.com/account/settings/messaging'),
         ]);
     }