net: lwm2m: fix max path size
in various places the path can contain leading slash
@@ -1398,7 +1398,7 @@ void lwm2m_rd_client_update(void);
/**
* @brief LwM2M path maximum length
*/
-#define LWM2M_MAX_PATH_STR_SIZE sizeof("65535/65535/65535/65535")
+#define LWM2M_MAX_PATH_STR_SIZE sizeof("/65535/65535/65535/65535")
/**
* @brief Helper function to print path objects' contents to log
