Explicit check for existence of chat_template (#1725)

`conversational` does not always imply chat_template. Example:
https://huggingface.co/facebook/blenderbot-400M-distill/blob/main/README.md

In our internal codebase we auto-set `conversational` if a chat template
exists, but the opposite is not always true. The model above has an
explicit `conversational` tag, but no chat template.

See #1722

---------

Co-authored-by: Julien Chaumond <[email protected]>

Author: pcuenca

packages/tasks/src/model-data.ts

@@ -44,6 +44,10 @@ export interface ModelData {
 			quant_method?: string;
 		};
 		tokenizer_config?: TokenizerConfig;
+		processor_config?: {
+			chat_template?: string;
+		};
+		chat_template_jinja?: string;
 		adapter_transformers?: {
 			model_name?: string;
 			model_class?: string;

packages/tasks/src/model-libraries-snippets.ts

@@ -1476,6 +1476,11 @@ export const terratorch = (model: ModelData): string[] => [
 model = BACKBONE_REGISTRY.build("${model.id}")`,
 ];
 
+const hasChatTemplate = (model: ModelData): boolean =>
+	model.config?.tokenizer_config?.chat_template !== undefined ||
+	model.config?.processor_config?.chat_template !== undefined ||
+	model.config?.chat_template_jinja !== undefined;
+
 export const transformers = (model: ModelData): string[] => {
 	const info = model.transformersInfo;
 	if (!info) {
@@ -1498,7 +1503,7 @@ export const transformers = (model: ModelData): string[] => {
 			`${processorVarName} = ${info.processor}.from_pretrained("${model.id}"` + remote_code_snippet + ")",
 			`model = ${info.auto_model}.from_pretrained("${model.id}"` + remote_code_snippet + ")"
 		);
-		if (model.tags.includes("conversational")) {
+		if (model.tags.includes("conversational") && hasChatTemplate(model)) {
 			if (model.tags.includes("image-text-to-text")) {
 				autoSnippet.push(
 					"messages = [",