Incorrect Decoding of Cancellation Message in SDK (Spaces Replaced with '+')

[MussaCharles]

When a user cancels the payment process using the SDK, the returned string is incorrectly decoded, replacing spaces with '+' signs. For example, the expected cancellation message "결제가 사용자에 의해 취소되었습니다" is returned as "결제가+사용자에+의해+취소되었습니다".

This issue appears to be an encoding problem where spaces are not correctly handled.

Suggested Fix

1. Investigate the method responsible for decoding the return string in the SDK's payment cancellation code.
2. Modify the decoding process to correctly interpret spaces, possibly by adjusting the encoding method or replacing '+' signs with spaces.

Below is a sample response for the mentioned issue which is sent via the following delegate

public protocol TossPaymentsDelegate: AnyObject {
    func handleSuccessResult(_ success: TossPaymentsResult.Success)
    func handleFailResult(_ fail: TossPaymentsResult.Fail)
}

Issue

Fail(errorCode: "PAY_PROCESS_CANCELED", errorMessage: "결제가+사용자에+의해+취소되었습니다.", orderId: Optional("")