move / tweak sharing templates

Shared/views/SharingListView.swift

@@ -146,6 +146,11 @@ struct SharingListView: View {
 
 struct SharingView_Previews: PreviewProvider {
     static var previews: some View {
-        SharingListView()
+        Group {
+            SharingListView()
+            
+            SharingListView()
+                .preferredColorScheme(.dark)
+        }
     }
 }