Clarify Callback Usage in usePaystackPayment Hook Documentation

[Chimaobi098]

This PR updates the documentation for the usePaystackPayment hook to clarify that the success and close callbacks must be passed as an object, i.e. using initializePayment({ onSuccess, onClose }) rather than as separate arguments i.e. initializePayment(onSuccess, onClose).

I initially tried using the separate arguments approach, but the callbacks weren’t being recognized and the onSuccess function was never fired even though the transaction was successful. After some investigation, I discovered that wrapping the callbacks in curly braces (to pass them as an object) resolved the issue.

This update should improve clarity and help prevent confusion for developers using this hook. Please review and let me know if any further adjustments are needed.