BTDXCLTS-1908 clarify 3ds amount param (#521)
BTDXCLTS-1908 clarify 3ds amount param (#521)

* BTDXCLTS-1908 clarify 3ds amount param

* further clarify 3ds amount param

braintree/braintree_ios,braintree/braintree_ios,braintree/braintree_ios,braintree/braintree_ios