check decoder_inputs_embeds is None before shifting labels (#19671)

templates/adding_a_new_model/cookiecutter-template-{{cookiecutter.modelname}}/modeling_{{cookiecutter.lowercase_modelname}}.py

@@ -2833,7 +2833,7 @@ class {{cookiecutter.camelcase_modelname}}ForConditionalGeneration({{cookiecutte
             if use_cache:
                 logger.warning("The `use_cache` argument is changed to `False` since `labels` is provided.")
             use_cache = False
-            if decoder_input_ids is None:
+            if decoder_input_ids is None and decoder_inputs_embeds is None:
                 decoder_input_ids = shift_tokens_right(labels, self.config.pad_token_id, self.config.decoder_start_token_id)
 
         outputs = self.model(