`filer_folder_from_path`: properly handle empty strings and None
`filer_folder_from_path`: properly handle empty strings and None

lawzou/shoop,suutari/shoop,shoopio/shoop,suutari/shoop,taedori81/shoop,lawzou/shoop,shawnadelic/shuup,shoopio/shoop,akx/shoop,taedori81/shoop,shawnadelic/shuup,akx/shoop,hrayr-artunyan/shuup,shawnadelic/shuup,hrayr-artunyan/shuup,jorge-marques/shoop,suutari-ai/shoop,lawzou/shoop,suutari/shoop,hrayr-artunyan/shuup,jorge-marques/shoop,akx/shoop,suutari-ai/shoop,taedori81/shoop,suutari-ai/shoop,shoopio/shoop,jorge-marques/shoop