fix: navigation fallthrough in 'Get MCU ID' (Advanced Menu) (#762)

* fix: corrected back navigation in advanced menu in reference to #761

* ci: add delay after warning when no MCUs are found

kiauh/components/klipper_firmware/menus/klipper_flash_menu.py

@@ -236,9 +236,11 @@ class KlipperSelectMcuConnectionMenu(BaseMenu):
         if len(self.flash_options.mcu_list) < 1:
             Logger.print_warn("No MCUs found!")
             Logger.print_warn("Make sure they are connected and repeat this step.")
+            time.sleep(3)
+            return
 
         # if standalone is True, we only display the MCUs to the user and return
-        if self.__standalone and len(self.flash_options.mcu_list) > 0:
+        if self.__standalone:
             Logger.print_ok("The following MCUs were found:", prefix=False)
             for i, mcu in enumerate(self.flash_options.mcu_list):
                 print(f"   ● MCU #{i}: {Color.CYAN}{mcu}{Color.RST}")