[Auth]: Evaluate `Auth.auth().canHandle(_ url: URL) -> Bool` in a scene delegate context

This is not a breaking change. Added to milestone 12 for reassessment if not address beforehand.

### Description

Auth's `canHandle(_ url: URL)` API doesn't fit as well in the scene delegate world as it does in the app delegate world. In the app delegate of the below scene delegate method, a boolean needs to be returned to the API returns a Bool. That doesn't make sense in the scene delegate world (see below delegate method's lack of return type).

Two approaches:
- Add `@discardableResult` to the API
- Add new API for scene delegate context (e.g. `canHandle(_ urlContext: URLContext) -> Void` to the API surface

```swift
func scene(_ scene: UIScene, openURLContexts URLContexts: Set) {
for urlContext in URLContexts {
let url = urlContext.url
_ = Auth.auth().canHandle(url)
}
}
```

### API Proposal

_No response_

### Firebase Product(s)

Authentication