[localize] add `currencyDisplay` to FormatNumberOptions types

[tlouisse]

https://github.com/ing-bank/lion/blob/master/packages/localize/types/LocalizeMixinTypes.d.ts#L33

See: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat/NumberFormat

(apparently this info got lost in TS 4.5)