Revert "feat(notifications): deduplicate repeated email alerts"

This reverts commit 8c1405e168.

app/Notifications/Server/DockerCleanupSuccess.php

@@ -21,16 +21,6 @@ class DockerCleanupSuccess extends CustomEmailNotification
         return $notifiable->getEnabledChannels('docker_cleanup_success');
     }
 
-    public function deduplicationKey(object $notifiable, string $channel): ?string
-    {
-        return "docker-cleanup-success:server:{$this->server->uuid}:message:".hash('sha256', $this->message);
-    }
-
-    public function deduplicateFor(): int
-    {
-        return 21600;
-    }
-
     public function toMail(): MailMessage
     {
         $mail = new MailMessage;