fix null safety

android/app/src/main/AndroidManifest.xml

@@ -1,7 +1,6 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.mokkon.fcs.fcs">
    <application
-        android:label="fcs"
         android:icon="@mipmap/ic_launcher">
         <activity
             android:name=".MainActivity"

android/app/src/main/java/com/mokkon/fcs/fcs/Application.java

@@ -0,0 +1,13 @@
+package com.mokkon.fcs.fcs;
+
+ import io.flutter.app.FlutterApplication;
+import io.flutter.plugin.common.PluginRegistry;
+import io.flutter.plugins.GeneratedPluginRegistrant;
+
+
+public class Application extends FlutterApplication  {
+  @Override
+  public void onCreate() {
+    super.onCreate();
+  }
+}

android/app/src/main/res/values/strings.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="app_name">FCS</string>
+</resources>