Fix infer library for sentence transformers models (#1832)

Author: echarlaix

optimum/exporters/tasks.py

@@ -1671,16 +1671,17 @@ def _infer_library_from_model(
         if library_name is not None:
             return library_name
 
-        if (
+        # SentenceTransformer models have no config attributes
+        if hasattr(model, "_model_config"):
+            library_name = "sentence_transformers"
+        elif (
             hasattr(model, "pretrained_cfg")
             or hasattr(model.config, "pretrained_cfg")
             or hasattr(model.config, "architecture")
         ):
             library_name = "timm"
         elif hasattr(model.config, "_diffusers_version") or getattr(model, "config_name", "") == "model_index.json":
             library_name = "diffusers"
-        elif hasattr(model, "_model_config"):
-            library_name = "sentence_transformers"
         else:
             library_name = "transformers"
         return library_name
@@ -1905,7 +1906,6 @@ def get_model_from_task(
         model_class = TasksManager.get_model_class_for_task(
             task, framework, model_type=model_type, model_class_name=model_class_name, library=library_name
         )
-
         if library_name == "timm":
             model = model_class(f"hf_hub:{model_name_or_path}", pretrained=True, exportable=True)
             model = model.to(torch_dtype).to(device)