set ndkVersion to align with Flutter's NDK version

Author: MaikuB

flutter_local_notifications/example/android/app/build.gradle

@@ -25,6 +25,7 @@ if (flutterVersionName == null) {
 android {
     namespace 'com.dexterous.flutter_local_notifications_example'
     compileSdk 35
+    ndkVersion = flutter.ndkVersion
 
     sourceSets {
         main.java.srcDirs += 'src/main/kotlin'