fix: init previous_menu in menus

Signed-off-by: Dominik Willner <th33xitus@gmail.com>

kiauh/core/menus/backup_menu.py

@@ -32,6 +32,7 @@ from utils.constants import COLOR_CYAN, RESET_FORMAT, COLOR_YELLOW
 class BackupMenu(BaseMenu):
     def __init__(self, previous_menu: Optional[Type[BaseMenu]] = None):
         super().__init__()
+        self.previous_menu = previous_menu
 
     def set_previous_menu(self, previous_menu: Optional[Type[BaseMenu]]) -> None:
         from core.menus.main_menu import MainMenu