presentPaymentMethodSelection
Launch the PaymentMethodsActivity to allow the user to select a payment method, or to add a new one.
The initial selected Payment Method ID uses the following logic.
If {@param userSelectedPaymentMethodId} is specified, use that
If the instance's PaymentSessionData.paymentMethod is non-null, use that
If the instance's PaymentSessionPrefs.getPaymentMethod is non-null, use that
Otherwise, choose the most recently added Payment Method
Parameters
selectedPaymentMethodId
if non-null, the ID of the Payment Method that should be initially selected on the Payment Method selection screen