Stripe void: response.charges diverges (HS object vs UCS null) in shadow validation

Shadow-validation diff **juspay/hyperswitch-cloud#16999** — connector `stripe`, flow `void`: `router.typeDiff:response.Ok.TransactionResponse.charges` (HS populates `charges`, UCS returns null).

Root cause: the void gRPC request to UCS (`PaymentServiceVoidRequest`) had no `split_payments` field, so HS could not forward the payment's `split_payments` on void; UCS derives the void response `splits`/`charges` from it. Fixed by adding `split_payments` to the void request (UCS) and mapping it from `PaymentsCancelData.split_payments` (HS).

Depends on UCS PR juspay/connector-service#1677.

Review the UCS PaymentServiceVoidRequest and the HS PaymentsCancelData.split_payments mapping, using UCS PR juspay/connector-service#1677 as the dependency context. Verify the void request carries the payment splits and rerun the Stripe void shadow validation; done means response.charges no longer differs between HS and UCS.

Written by the indexing model from the issue text.