Update examples to use async/await

[yuki-stripe]

Summary

Update examples to use async/await with new confirm handler. Used claude.

Testing

Sanity checked each example still loads + confirms

Changelog

N/A

[github-actions]

⚠️ Public API changes detected:

StripeFinancialConnections

+ @_Concurrency.MainActor final public func present(from presentingViewController: UIKit.UIViewController) async -> StripeFinancialConnections.FinancialConnectionsSheet.Result
+ @_Concurrency.MainActor final public func presentForToken(from presentingViewController: UIKit.UIViewController) async -> StripeFinancialConnections.FinancialConnectionsSheet.TokenResult

If you are adding a new public API consider the following:

• Do these APIs need to be public or can they be protected with @_spi(STP)?
• If these APIs need to be public, assess whether they require an API review.

If you are modifying or removing a public API:

• Does this require a breaking version change?
• Do these changes require API review?

If you confirm these APIs need to be added/updated and have undergone necessary review, add the label modifies public API to this PR to acknowledge and bypass this check.

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