Replace withCheckedThrowingContinuation Calls With withUnsafeThrowingContinuation

[AlexNsbmr]

First, thank you for maintaining this awesome library! 🙏

I wanted to report an issue we’re experiencing when using withCheckedThrowingContinuation on iOS 18, which is causing several crashes in our app. After investigating, it seems like replacing withCheckedThrowingContinuation with withUnsafeThrowingContinuation resolves the issue.

For reference, the team at RevenueCat has implemented a similar fix, and you can check out their approach here:
RevenueCat/purchases-ios#4286

Would it be possible to make this update in the library as well?

Thank you for your attention to this issue!

[AvdLee]

@AlexNsbmr thanks for letting us know! Feel free to open a PR with the fix, happy to give it a review 🙏