productPriceString does not contain currency symbol on iOS

[samarthagarwalqb]

productPriceString in the Product objects returned in the response of retrieveProducts method does not contain the currency symbol on iOS. It only contains a numerical value. On Android, it contains the symbol as well as the amount. Here is an example.

On Android, the value of productPriceString would be something like $9.95 while on iOS, it will only contain 9.95. It does not contain the $ symbol as part of the String.

This should be consistent across both platforms.