feat: delete session when user is not found

src/auth/auth.service.ts

@@ -29,7 +29,10 @@ export async function getSession(
   if (session === null) return null;
 
   const user = await userModel.findById(session.user);
-  if (user === null) return null;
+  if (user === null) {
+    await deleteSession(sessionId);
+    return null;
+  }
 
   return {
     sid: session.id,