Update file/folder chooser back icon, part of #1664.

files/src/main/res/drawable/icon_return_dark.xml

@@ -1,13 +1,10 @@
 <vector
     xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:tools="http://schemas.android.com/tools"
-    android:autoMirrored="true"
-    android:height="36dp"
+    android:height="24dp"
     android:viewportHeight="24.0"
     android:viewportWidth="24.0"
-    android:width="36dp"
-    tools:ignore="UnusedAttribute,VectorRaster">
+    android:width="24dp">
   <path
       android:fillColor="#424242"
-      android:pathData="M19,7v4H5.83l3.58,-3.59L8,6l-6,6 6,6 1.41,-1.41L5.83,13H21V7z"/>
+      android:pathData="M20,11H7.83l5.59,-5.59L12,4l-8,8 8,8 1.41,-1.41L7.83,13H20v-2z"/>
 </vector>

files/src/main/res/drawable/icon_return_light.xml

@@ -1,13 +1,10 @@
 <vector
     xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:tools="http://schemas.android.com/tools"
-    android:autoMirrored="true"
-    android:height="36dp"
+    android:height="24dp"
     android:viewportHeight="24.0"
     android:viewportWidth="24.0"
-    android:width="36dp"
-    tools:ignore="UnusedAttribute,VectorRaster">
+    android:width="24dp">
   <path
       android:fillColor="#EEEEEE"
-      android:pathData="M19,7v4H5.83l3.58,-3.59L8,6l-6,6 6,6 1.41,-1.41L5.83,13H21V7z"/>
+      android:pathData="M20,11H7.83l5.59,-5.59L12,4l-8,8 8,8 1.41,-1.41L7.83,13H20v-2z"/>
 </vector>