fix oauth2 secret handling

create allways a new one as we have access to the oauth2 server

lenticular_cloud/views/oauth2.py

@@ -92,7 +92,7 @@ def init_login_manager(app: Flask) -> None:
     oauth2.register(
         name="custom",
         client_id=hydra_service.client_id,
-        client_secret=app.config['OAUTH_SECRET'],
+        client_secret=hydra_service.client_secret,
         server_metadata_url=f'{base_url}/.well-known/openid-configuration',
         access_token_url=f"{base_url}/oauth2/token",
         authorize_url=f"{base_url}/oauth2/auth",