fix Gradle warning about deprecated apply script method

@@ -62,7 +62,3 @@ android {
 flutter {
     source '../..'
 }
-
-dependencies {
-    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
-}

-buildscript {
-    ext.kotlin_version = '1.9.22'
-    repositories {
-        google()
-        mavenCentral()
-    }
-
-    dependencies {
-        classpath 'com.android.tools.build:gradle:8.2.2'
-        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
-    }
-}
-
 allprojects {
     repositories {
         google()

@@ -5,12 +5,21 @@ pluginManagement {
         def flutterSdkPath = properties.getProperty("flutter.sdk")
         assert flutterSdkPath != null, "flutter.sdk not set in local.properties"
         return flutterSdkPath
-    }
-    settings.ext.flutterSdkPath = flutterSdkPath()
+    }()
+
+    includeBuild("$flutterSdkPath/packages/flutter_tools/gradle")
 
-    includeBuild("${settings.ext.flutterSdkPath}/packages/flutter_tools/gradle")
+    repositories {
+        google()
+        mavenCentral()
+        gradlePluginPortal()
+    }
 }
 
-include ":app"
+plugins {
+    id "dev.flutter.flutter-plugin-loader" version "1.0.0"
+    id "com.android.application" version "8.2.2" apply false
+    id "org.jetbrains.kotlin.android" version "1.9.22" apply false
+}
 
-apply from: "${settings.ext.flutterSdkPath}/packages/flutter_tools/gradle/app_plugin_loader.gradle"
+include ":app"
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