[ios] Fixes InfobarBannerDismissal animation.

This regression was introduced here:
https://chromium-review.googlesource.com/c/chromium/src/+/1974894

We need to respect the animated flag, this is really hard to test
since we can't tell on eg if the dismissal was animated or not.

Bug: 1049088
Change-Id: I9e4326f4fb7885146191bd39e9ebeded8c1c9ae4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2067642
Auto-Submit: Sergio Collazos <sczs@chromium.org>
Commit-Queue: Chris Lu <thegreenfrog@chromium.org>
Reviewed-by: Chris Lu <thegreenfrog@chromium.org>
Cr-Commit-Position: refs/heads/master@{#743443}

ios/chrome/browser/ui/infobars/coordinators/infobar_coordinator.mm

@@ -446,7 +446,7 @@ const CGFloat kBannerOverlapWithOmnibox = 5.0;
       self.baseViewController.presentedViewController ==
           self.bannerViewController) {
     [self infobarBannerWillBeDismissed:userInitiated];
-    [self.baseViewController dismissViewControllerAnimated:YES
+    [self.baseViewController dismissViewControllerAnimated:animated
                                                 completion:completion];
   } else if (completion) {
     completion();