Make auto-play button style more explanatory (#3952)

Co-authored-by: Bnyro <bnyro@tutanota.com>

app/src/main/res/drawable/ic_pause_circle.xml

@@ -0,0 +1,11 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:tint="?colorControlNormal"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+  <path
+      android:pathData="m8.4,16.8h2.4L10.8,7.2L8.4,7.2ZM12,0C5.376,0 0,5.376 0,12 0,18.624 5.376,24 12,24 18.624,24 24,18.624 24,12 24,5.376 18.624,0 12,0ZM12,21.6c-5.292,0 -9.6,-4.308 -9.6,-9.6 0,-5.292 4.308,-9.6 9.6,-9.6 5.292,0 9.6,4.308 9.6,9.6 0,5.292 -4.308,9.6 -9.6,9.6zM13.2,16.8h2.4L15.6,7.2h-2.4z"
+      android:strokeWidth="1.2"
+      android:fillColor="@android:color/white"/>
+</vector>

app/src/main/res/drawable/player_switch_thumb.xml

@@ -1,6 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
+     <item android:state_checked="false"
+        android:drawable="@drawable/ic_pause_circle"/>
 
-    <item android:drawable="@drawable/ic_play_circle"/>
+    <item android:state_checked="true"
+        android:drawable="@drawable/ic_play_circle"/>
 
 </selector>