Subscriber user can choose Carryover option when they select Stop Spending option to "End Contract" - UI Only

When user chooses to End Contract (either scheduled or immediately) and selects the Stop Spending option the user is offered two choices regarding the remaining budget carryover balance:

Zero out the Budget Carryover Balance (so that the subsequent deployment will not reinstate any remaining budget carryover balance for the merchant).
Keep the Budget Carryover Balance (so that the subsequent deployment will reinstate any remaining budget carryover balance for the merchant).

The second option is expected to be used for merchants that may have billing issues or request to be temporarily offline for vacation.

This user story is strictly the UI presenting these choices and persisting the user's selection. Implementation downstream is a separate story.