Version 12.10.1

### 12.10.1
-   Changes
    - General (iOS): Change AppDelegate swizzling logic to not use `objc_copyClassList`,
      which was causing a slow startup, and crashes on iOS 15.
      ([#1268](https://github.com/firebase/firebase-unity-sdk/issues/1268)).
    - General (iOS): Added an option to explicitly specify your app's `AppDelegate` class
      name via the `FirebaseAppDelegateClassName` key in `Info.plist`. This
      provides a more direct way for Firebase to interact with your specified
      AppDelegate. See "Platform Notes > iOS Method Swizzling >
      Specifying Your AppDelegate Class Directly (iOS)" for details.