[iOS][MF] Disable accessory view animation

Disabling the manual fill accessory animation until the suggestion
animation is done. Animating the suggestions disappearing is hard and
it looks better with no animations than with one animation in one part
and no animation in the other.

Bug: 845472, 905660, 905651
Change-Id: Ic0d9de58a85b0e5366105102f0bf3706e5ce42ba
Reviewed-on: https://chromium-review.googlesource.com/c/1341995Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609348}

ios/chrome/browser/ui/autofill/manual_fill/manual_fill_accessory_view_controller.mm

@@ -39,7 +39,7 @@ constexpr CGFloat ManualFillIconsRightInset = 24;
 
 }  // namespace
 
-static NSTimeInterval MFAnimationDuration = 0.20;
+static NSTimeInterval MFAnimationDuration = 0;
 
 @interface ManualFillAccessoryViewController ()