Revert "[iOS] Makes bottom toolbar visible when modal view disappears"

This reverts commit df86a3d6.

Reason for revert: Toolbars remain displayed when they shouldn't.


Original change's description:
> [iOS] Makes bottom toolbar visible when modal view disappears
> 
> This Cl makes the bottom toolbar visible when initiating a drag down
> to close a modal setting view.
> 
> Bug: 1106665
> Change-Id: I519fac84a18c36c6838384241af01f1c57a824b0
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2302633
> Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
> Commit-Queue: Ewann Pellé <ewannpv@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#789454}

TBR=sdefresne@chromium.org,ewannpv@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 1106665
Change-Id: Ic0e6dc70ea878deb0b0be852fa84bab32b4124f3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2309691Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Ewann Pellé <ewannpv@chromium.org>
Cr-Commit-Position: refs/heads/master@{#790319}

ios/chrome/browser/ui/settings/settings_root_table_view_controller.mm

@@ -143,6 +143,7 @@ const CGFloat kActivityIndicatorDimensionIPhone = 56;
 
 - (void)viewWillDisappear:(BOOL)animated {
   [super viewWillDisappear:animated];
+  [self.navigationController setToolbarHidden:YES animated:YES];
 }
 
 - (void)setEditing:(BOOL)editing animated:(BOOL)animated {