Update in series.py the _get_existing_seasons method

By changing the searched tag to `Name`, I stopped getting timeouts generated by `_wait_for_season`.

app/src/series.py

@@ -225,7 +225,7 @@ class Show:
         path: str = f"Shows/{series_id}/Seasons"
         all_seasons: dict = Jellyfin().get(path)
 
-        return [str(i.get("IndexNumber")) for i in all_seasons["Items"]]
+        return [str(i.get("Name")) for i in all_seasons["Items"]]
 
     def delete_folders(self, folders: list[str]) -> None:
         """delete temporary folders created"""