Assume CC numbers are strings
Assume CC numbers are strings

We honestly should be doing this anyway; now, enforce it, and take
advantage of it to cut down on string conversions.

Follow-up to conversation in #2983

3926 tests, 68184 assertions, 0 failures, 0 errors, 0 pendings, 2 omissions, 0 notifications
100% passed

curiousepic/active_merchant,Shopify/active_merchant,atxwebs/active_merchant,HealthWave/active_merchant,activemerchant/active_merchant,davidsantoso/active_merchant,pinpayments/active_merchant,customerlobby/active_merchant,appfolio/active_merchant,taf2/active_merchant,varyonic/active_merchant,Simplero/active_merchant,planetargon/active_merchant,vampirechicken/active_merchant,vanboom/active_merchant,buttercloud/active_merchant,lcn-com-dev/active_merchant,QuickPay/active_merchant