fix: Fix Android example app build error

Author: Dev-hwang

example/android/app/build.gradle

@@ -26,6 +26,7 @@ android {
     namespace "com.pravera.flutter_foreground_task_example"
 
     compileSdk 35
+    ndkVersion = flutter.ndkVersion
 
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_11

example/android/gradle.properties

@@ -1,3 +1,4 @@
-org.gradle.jvmargs=-Xmx1536M
+org.gradle.jvmargs=-Xmx4G -XX:+HeapDumpOnOutOfMemoryError
 android.useAndroidX=true
 android.enableJetifier=true
+android.enableR8=true