Fix Overdraw lint warning.

Signed-off-by: ZetaTom <70907959+ZetaTom@users.noreply.github.com>

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

@@ -22,8 +22,7 @@
     android:id="@+id/upload_files_layout"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:orientation="vertical"
-    android:background="@color/bg_default">
+    android:orientation="vertical">
 
     <include
         android:id="@+id/toolbar_layout"
@@ -39,6 +38,7 @@
             android:id="@android:id/list"
             android:layout_width="match_parent"
             android:layout_height="match_parent"
+            android:background="@color/bg_default"
             android:divider="@color/transparent"
             android:dividerHeight="0dip"
             android:nestedScrollingEnabled="true"
@@ -59,6 +59,7 @@
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
+        android:background="@color/bg_default"
         android:gravity="center"
         android:orientation="horizontal"
         android:padding="@dimen/standard_padding">