fix(examples): use 'n' instead of '0'/'false' for bool Kconfig defaults

'0' and 'false' are not valid values for a bool symbol. The parser emits
a note and falls back to 'n', so the resulting configuration is correct
but the build is noisy. Set the two remaining example symbols to
'default n' to make the value explicit and silence the note.

examples/wifi/scan/main/Kconfig.projbuild

@@ -9,7 +9,7 @@ menu "Example Configuration"
 
     config EXAMPLE_USE_SCAN_CHANNEL_BITMAP
         bool "Scan only non overlapping channels using Channel bitmap"
-        default 0
+        default n
         help
             Enable this to scan only the non overlapping channels i.e 1,6,11 by mentioning a channel bitmap
             in scan config. If you wish to scan a different set of specific channels, please edit the channel_list