[iOS][Settings] Fixes ChromeTableViews background color

This CL fixes the background color of ChromeTableViews.

Bug: 922511
Change-Id: I47662d867da44444902de17c40a399c9b20f4399
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2593111Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Auto-Submit: Ewann Pellé <ewannpv@chromium.org>
Commit-Queue: Ewann Pellé <ewannpv@chromium.org>
Cr-Commit-Position: refs/heads/master@{#837055}

ios/chrome/browser/ui/table_view/chrome_table_view_styler.mm

@@ -22,7 +22,7 @@
           [UIColor colorNamed:kSecondaryBackgroundColor];
       _cellBackgroundColor = UIColor.cr_secondarySystemGroupedBackgroundColor;
     } else {
-      _tableViewBackgroundColor = UIColor.cr_systemGroupedBackgroundColor;
+      _tableViewBackgroundColor = UIColor.cr_systemBackgroundColor;
     }
   }
   return self;