window-slot: Use accessor function to get current location

In function update_search_information() which may be called when the slot is
in the process of updating it's location. Use the location accessor function
nautilus_window_slot_get_current_location() which returns the correct location
when the slot is in the process of updating it's location related data
structures.
Status Job ID Name Coverage
  Test
passed #808316
flatpak
flatpak devel

00:13:45

passed #808317
style check

00:01:06