Fix toolbar shadow in conversation list.

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

@@ -149,6 +149,7 @@
         android:layout_height="5dp"
         android:background="@drawable/toolbar_shadow"
         android:visibility="gone"
+        android:elevation="100dp"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toBottomOf="@id/toolbar_barrier"