Project cleanup; removed unused resources and test classes. Fixed memory leak bug in DataFetcher.kt

app/src/main/res/layout/welcome_screen.xml

@@ -1,8 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
-    xmlns:tools="http://schemas.android.com/tools"
-    android:id="@+id/linearLayout"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
 
@@ -22,7 +20,6 @@
         app:srcCompat="@drawable/animated_check" />
 
     <TextView
-        android:id="@+id/txtHaveFun"
         android:layout_width="0dp"
         android:layout_height="wrap_content"
         android:layout_marginStart="8dp"