refactor(notifications): Improve transactional email settings handling

- Replace `! $type` checks with `blank($type)` for consistency
- Modify email settings configuration to handle null/disabled states
- Ensure proper fallback and configuration of email providers

app/Notifications/Channels/TransactionalEmailChannel.php

@@ -35,7 +35,7 @@ class TransactionalEmailChannel
     private function bootConfigs(): void
     {
         $type = set_transanctional_email_settings();
-        if (! $type) {
+        if (blank($type)) {
             throw new Exception('No email settings found.');
         }
     }