[SHv2] Update Safety Hub Chromenu icon

This CL updates the Chromenu icon for Safety Hub to the checkered shield
symbol ("security" on https://fonts.google.com/).

Before: https://screenshot.googleplex.com/5PfbcEnrm5Ltkzr
After: https://screenshot.googleplex.com/7si5KvCT8CP58NB

Bug: 1443466
Change-Id: I0be2e70a3021759475b17d33550f0335db0ac00d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4988365
Reviewed-by: Alex Ilin <alexilin@chromium.org>
Auto-Submit: Tom Van Goethem <tov@chromium.org>
Commit-Queue: Alex Ilin <alexilin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1217029}

chrome/app/vector_icons/BUILD.gn

@@ -190,7 +190,6 @@ aggregate_vector_icons("chrome_vector_icons") {
     "resize_handle.icon",
     "sad_tab.icon",
     "safety_check.icon",
-    "safety_hub.icon",
     "save_group.icon",
     "save_group_refresh.icon",
     "save_page.icon",

chrome/browser/ui/toolbar/app_menu_model.cc

@@ -1482,7 +1482,7 @@ void AppMenuModel::Build() {
         safety_hub_menu_notification_service->GetNotificationToShow();
     if (notification.has_value()) {
       const auto safety_hub_icon = ui::ImageModel::FromVectorIcon(
-          kSafetyHubIcon, ui::kColorMenuIcon, kDefaultIconSize);
+          kSecurityIcon, ui::kColorMenuIcon, kDefaultIconSize);
       AddItemWithIcon(notification->command, notification->label,
                       safety_hub_icon);
       need_separator = true;