Ignore cancelled redirects, add OS debug logging

What changes are you making?

Adds OS debug logging ShopifyCheckoutSheetKit.configuration.logLevel = .error
Ignores URL redirects cancellations in the webview

Before you merge

[!IMPORTANT]

[x] I've added tests to support my implementation

[x] I have read and agree with the Contribution Guidelines.

[x] I have read and agree with the Code of Conduct.

[ ] I've updated the README.

Checklist for releasing a new version

- [ ] I have bumped the version number in the [`podspec` file](https://github.com/Shopify/checkout-kit-swift/blob/main/ShopifyCheckoutKit.podspec#L2). - [ ] I have bumped the version number in the [README](https://github.com/Shopify/checkout-kit-swift/blob/main/README.md#packageswift). - [ ] I have added a [Changelog](https://github.com/shopify/checkout-sheet-kit-swift/blob/main/CHANGELOG.md) entry.

[!TIP] See the Contributing documentation for instructions on how to publish a new version of the library.

Shopify / checkout-sheet-kit-swift

Ignore cancelled redirects, add OS debug logging #225

What changes are you making?

Before you merge