SRC_119247: Shopping Cart: Cannot add service plan when in Shopping Cart. Out of stock message is showing

Problem: Conversion of service plan price from String type to BigDecimal fails if the cart price of the item contains decimal point (e.g. 65.00 will be converted to 0, because of validation method used).

Solution: use NumberUtils.isNumber to check if the cart price (in String type) can be converted to BigDecimal