[webview_flutter] Update Pigeon for Kotlin 1.8 compat (#10486)

Rolls Pigeon to 26.1.2 in `webview_flutter_android` to pick up a fix for a Kotlin 1.8 compatibility issue.

Fixes https://github.com/flutter/flutter/issues/178756

## Pre-Review Checklist

[^1]: Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling.
diff --git a/packages/webview_flutter/webview_flutter_android/CHANGELOG.md b/packages/webview_flutter/webview_flutter_android/CHANGELOG.md
index 25d44d0..67582ef 100644
--- a/packages/webview_flutter/webview_flutter_android/CHANGELOG.md
+++ b/packages/webview_flutter/webview_flutter_android/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 4.10.9
+
+* Fixes a compatibility issue with Kotlin 1.8.
+
 ## 4.10.8
 
 * Bumps com.android.tools.build:gradle from 8.12.1 to 8.13.1.
diff --git a/packages/webview_flutter/webview_flutter_android/android/src/main/java/io/flutter/plugins/webviewflutter/AndroidWebkitLibrary.g.kt b/packages/webview_flutter/webview_flutter_android/android/src/main/java/io/flutter/plugins/webviewflutter/AndroidWebkitLibrary.g.kt
index 7abf4fc..b025ed9 100644
--- a/packages/webview_flutter/webview_flutter_android/android/src/main/java/io/flutter/plugins/webviewflutter/AndroidWebkitLibrary.g.kt
+++ b/packages/webview_flutter/webview_flutter_android/android/src/main/java/io/flutter/plugins/webviewflutter/AndroidWebkitLibrary.g.kt
@@ -1,7 +1,7 @@
 // Copyright 2013 The Flutter Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
-// Autogenerated from Pigeon (v26.1.0), do not edit directly.
+// Autogenerated from Pigeon (v26.1.2), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 @file:Suppress("UNCHECKED_CAST", "ArrayInDataClass")
 
@@ -217,7 +217,7 @@
   }
 
   /** Retrieves the instance associated with identifier, if present, otherwise `null`. */
-  fun <T> getInstance(identifier: Long): T? {
+  fun <T : Any> getInstance(identifier: Long): T? {
     logWarningIfFinalizationListenerHasStopped()
     val instance = weakInstances[identifier] as IdentityWeakReference<T>?
     return instance?.get()
diff --git a/packages/webview_flutter/webview_flutter_android/lib/src/android_webkit.g.dart b/packages/webview_flutter/webview_flutter_android/lib/src/android_webkit.g.dart
index c19506c..64fb2ba 100644
--- a/packages/webview_flutter/webview_flutter_android/lib/src/android_webkit.g.dart
+++ b/packages/webview_flutter/webview_flutter_android/lib/src/android_webkit.g.dart
@@ -1,7 +1,7 @@
 // Copyright 2013 The Flutter Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
-// Autogenerated from Pigeon (v26.1.0), do not edit directly.
+// Autogenerated from Pigeon (v26.1.2), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 // ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name, unnecessary_import, no_leading_underscores_for_local_identifiers
 
diff --git a/packages/webview_flutter/webview_flutter_android/pubspec.yaml b/packages/webview_flutter/webview_flutter_android/pubspec.yaml
index 6898d00..ce83b55 100644
--- a/packages/webview_flutter/webview_flutter_android/pubspec.yaml
+++ b/packages/webview_flutter/webview_flutter_android/pubspec.yaml
@@ -2,7 +2,7 @@
 description: A Flutter plugin that provides a WebView widget on Android.
 repository: https://github.com/flutter/packages/tree/main/packages/webview_flutter/webview_flutter_android
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+webview%22
-version: 4.10.8
+version: 4.10.9
 
 environment:
   sdk: ^3.9.0
@@ -28,7 +28,7 @@
   flutter_test:
     sdk: flutter
   mockito: ^5.4.4
-  pigeon: ^26.1.0
+  pigeon: ^26.1.2
 
 topics:
   - html