feat: init SwiftUI library for FirebaseAuthSwiftUI

[russellwheatley]

Work in progress

[morganchen12]

Overall looks good. Had one architecture question for consideration.

[morganchen12]

Everything that's marked TODO can be done in a future PR.

[peterfriese]

Let's see if using SwiftUI's string localization is a more canonical way to support this.

See https://developer.apple.com/documentation/xcode/localizing-and-varying-text-with-a-string-catalog

[russellwheatley]

migrated to use string catalog : 5c31f91 (#1237)

Use SwiftUI string localization: 76fa8f3 (#1237)

[peterfriese]

This looks very similar to the nonce code we need to implement for Apple.

[russellwheatley]

moved to CommonUtils: 2923384 (#1237) for use with Apple package

[peterfriese]

This computed property does a lot. It is trying to sync with ATTrackingManager.trackingAuthorizationStatus, and also drives showUserTrackingAlert and limitedLogin.

We should simplify this.

[peterfriese]

Here is an alternative solution that feels cleaner:

  @State private var showUserTrackingAlert = false
  @State private var trackingAuthorizationStatus: ATTrackingManager.AuthorizationStatus = .notDetermined

  var isLimitedLogin: Bool {
    trackingAuthorizationStatus != .authorized
  }

  public init() {
    _trackingAuthorizationStatus = State(initialValue: ATTrackingManager.trackingAuthorizationStatus)
  }

  func requestTrackingPermission() {
    ATTrackingManager.requestTrackingAuthorization { status in
      Task { @MainActor in
        trackingAuthorizationStatus = status
        if status != .authorized {
          showUserTrackingAlert = true
        }
      }
    }
  }

[russellwheatley]

updated to reduce scope of binding: 0d5d8ba (#1237)

Not sure if you agree but a binding was still needed to stop toggle from switching if limited login wasn't possible.

[peterfriese]

Instead of changing this from inside a computed property, I would recommend using the onChange(of:) view modifier to listen to limitedLogin and update showUserTrackingAlert accordingly.

[peterfriese]

Instead of making assumptions about the grace period, it'd be better to make the call and handle the error.

See https://github.com/peterfriese/IdentityKit/blob/a9383206ef3dce073e3b64b6828ccb8d3b77315b/Sources/IdentityKit/Service/AccountService.swift#L68