fix(api): block invalid destination types and service deletions

app/Models/SwarmDocker.php

@@ -124,6 +124,6 @@ class SwarmDocker extends BaseModel
 
     public function attachedTo()
     {
-        return $this->applications?->count() > 0 || $this->databases()->count() > 0;
+        return $this->applications()->exists() || $this->databases()->count() > 0 || $this->services()->exists();
     }
 }