Computed getter which returns all options required to initialize
the PayPalCardFields instance.
If it changes, the instance of the PayPalCardFields instance
must be re-initialized.
PayPal JS SDK doesn't fetch the token comparing to
Datatrans Secure Fields JS SDK or Spreedly JS SDK,
so we specify this stub method here only to satisfy the interface.
Computed getter which returns all options required to initialize the PayPalCardFields instance. If it changes, the instance of the PayPalCardFields instance must be re-initialized.