[iOS][Thumb Strip] Fix recent tabs content offset

Before, -setInsetForRemoteTabs wasn't being called because the tab grid
was appearing in a different way (through the pan handler).

Fixed: 1155610
Change-Id: I1444624c2bf7d6c3c379f083205a520a731cab98
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2585095Reviewed-by: edchin <edchin@chromium.org>
Commit-Queue: Robbie Gibson <rkgibson@google.com>
Cr-Commit-Position: refs/heads/master@{#836195}

ios/chrome/browser/ui/tab_switcher/tab_grid/tab_grid_view_controller.mm

@@ -577,6 +577,7 @@ NSUInteger GetPageIndexFromPage(TabGridPage page) {
 - (void)didAnimateViewReveal:(ViewRevealState)viewRevealState {
   if (viewRevealState == ViewRevealState::Revealed) {
     self.scrollView.scrollEnabled = YES;
+    [self setInsetForRemoteTabs];
   }
 }