Fix regex pattern for model folder matching

Allows freqai to purge model train folders with non-alphanumeric characters in them (eg. hip3 pairs with hyphen)

freqtrade/freqai/data_drawer.py

@@ -446,7 +446,7 @@ class FreqaiDataDrawer:
 
         model_folders = [x for x in self.full_path.iterdir() if x.is_dir()]
 
-        pattern = re.compile(r"sub-train-(\w+)_(\d{10})")
+        pattern = re.compile(r"sub-train-([^_]+)_(\d{10})")
 
         delete_dict: dict[str, Any] = {}