url_helpers: Use snprintf in is_logged_in
url_helpers: Use snprintf in is_logged_in

Replace the strncpy with snprintf and then there's no need to set the
'\0' in the string as that will be done by snprintf.

Signed-off-by: Andrew Clayton <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@opentechlabs.co.uk>

ac000/receiptomatic