Remove dropdown caret for top nav redesign

- https://gitlab.com/gitlab-org/gitlab/-/issues/331331#note_596202895

app/assets/javascripts/nav/components/top_nav_app.vue

@@ -26,6 +26,7 @@ export default {
       menu-class="gl-mt-3! gl-max-w-none! gl-max-h-none! gl-sm-w-auto! js-top-nav-dropdown-menu"
       toggle-class="top-nav-toggle js-top-nav-dropdown-toggle gl-px-3!"
       no-flip
+      no-caret
     >
       <gl-dropdown-form>
         <top-nav-dropdown-menu

app/views/layouts/nav/_top_nav.html.haml

@@ -4,7 +4,6 @@
     %a.top-nav-toggle{ href: '#', type: 'button', data: { toggle: "dropdown" } }
       = sprite_icon('hamburger', css_class: "dropdown-icon")
       = view_model[:activeTitle]
-      = sprite_icon('chevron-down')
 
 .hidden
   - view_model[:shortcuts].each do |shortcut|