Decidir: Add support for `customer` object

[rachelkirk]

This adds support for adding email and id to the request nested in customer object.

CER-1189

Remote Tests: 26 tests, 92 assertions, 1 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications 96.1538% passed *1 remote test also failing on master

Unit Tests: 41 tests, 199 assertions, 0 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications 100% passed

Local Tests: 5833 tests, 79189 assertions, 4 failures, 1 errors, 0 pendings, 0 omissions, 0 notifications 99.9143% passed