Moved "Zero Subtotal Checkout" translation to Payment Module

Author: textarea

app/code/Magento/OfflinePayments/i18n/en_US.csv

@@ -21,5 +21,4 @@ Title,Title
 "Bank Transfer Payment","Bank Transfer Payment"
 Instructions,Instructions
 "Cash On Delivery Payment","Cash On Delivery Payment"
-"Zero Subtotal Checkout","Zero Subtotal Checkout"
 "Automatically Invoice All Items","Automatically Invoice All Items"

app/code/Magento/Payment/i18n/en_US.csv

@@ -58,3 +58,4 @@ No,No
 "Payment Methods Section","Payment Methods Section"
 "Payment Services","Payment Services"
 "Payment Methods","Payment Methods"
+"Zero Subtotal Checkout","Zero Subtotal Checkout"