Enable partial ASWebAuthenticationSession.Callback support

Related: #104

Author: ThexXTURBOXx

flutter_web_auth_2/ios/Classes/SwiftFlutterWebAuth2Plugin.swift

@@ -62,7 +62,13 @@ public class SwiftFlutterWebAuth2Plugin: NSObject, FlutterPlugin {
             }
 
             if #available(iOS 12, *) {
-                let session = ASWebAuthenticationSession(url: url, callbackURLScheme: callbackURLScheme, completionHandler: completionHandler!)
+                var _session: ASWebAuthenticationSession? = nil
+                if #available(iOS 17.4, *) {
+                    _session = ASWebAuthenticationSession(url: url, callback: ASWebAuthenticationSession.Callback.customScheme(callbackURLScheme), completionHandler: completionHandler!)
+                } else {
+                    _session = ASWebAuthenticationSession(url: url, callbackURLScheme: callbackURLScheme, completionHandler: completionHandler!)
+                }
+                let session = _session!
 
                 if #available(iOS 13, *) {
                     var rootViewController: UIViewController? = nil

flutter_web_auth_2/macos/Classes/FlutterWebAuth2Plugin.swift

@@ -40,7 +40,14 @@ public class FlutterWebAuth2Plugin: NSObject, FlutterPlugin, ASWebAuthentication
                 result(url.absoluteString)
             }
 
-            let session = ASWebAuthenticationSession(url: url, callbackURLScheme: callbackURLScheme, completionHandler: completionHandler)
+            var _session: ASWebAuthenticationSession? = nil
+            if #available(macOS 14.4, *) {
+                _session = ASWebAuthenticationSession(url: url, callback: ASWebAuthenticationSession.Callback.customScheme(callbackURLScheme), completionHandler: completionHandler)
+            } else {
+                _session = ASWebAuthenticationSession(url: url, callbackURLScheme: callbackURLScheme, completionHandler: completionHandler)
+            }
+            let session = _session!
+
             if let preferEphemeral = options["preferEphemeral"] as? Bool {
                 session.prefersEphemeralWebBrowserSession = preferEphemeral
             }