Apply suggestion from @Copilot

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

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-([^_]+)_(\d{10})")
+        pattern = re.compile(r"^sub-train-(.+)_(\d{10})$")
 
         delete_dict: dict[str, Any] = {}