Fix additional UnboundLocalError for 'time' variable in WiFi scanning

- Removed second local import of 'time' module in scan_and_select_best_wifi method
- This was another instance of the same variable shadowing issue
- Both scan_wifi_networks and scan_and_select_best_wifi methods had local time imports
- Now both methods use the globally imported time module correctly
- WiFi scanning and network selection should work without any variable scoping errors

This completely resolves the UnboundLocalError issues in WiFi network scanning
by ensuring no local imports shadow the globally imported time module.

autoinstaller_gui/autoinstallergui.py

@@ -1205,7 +1205,6 @@ class AutoInstallerGUI(QMainWindow):
         try:
             # Enable interface for scanning
             subprocess.run(['ip', 'link', 'set', self.selected_interface, 'up'], check=True)
-            import time
             time.sleep(2)
 
             # Scan networks