gpapf-save-national-format.php: Added new snippet.

Co-authored-by: Saif Sultan <saif@gravitywiz.com>

Author: matty0501

gp-advanced-phone-field/gpapf-save-national-format.php

@@ -16,7 +16,9 @@
 
 	$proto             = gp_advanced_phone_field()->get_phone_number_proto( $value );
 	$phone_number_util = \libphonenumber\PhoneNumberUtil::getInstance();
-
+	if ( ! $proto ) {
+		return $value;
+	}
 	return $phone_number_util->format( $proto, \libphonenumber\PhoneNumberFormat::NATIONAL );
 
 }, 10, 5 );