Revert "Revert "Allow nested sub-menus in the ActionMenu component" (primer#3638)"

This reverts commit 668a48f.

Author: HDinger

.changeset/forty-ghosts-admire.md

@@ -0,0 +1,5 @@
+---
+'@primer/view-components': minor
+---
+
+Introduce nested menus for Primer::Alpha::ActionMenu

.playwright/screenshots/snapshots.test.ts-snapshots/primer/beta/breadcrumbs/default/default.png

@@ -1,28 +1,3 @@
 <%= render Primer::BaseComponent.new(**@system_arguments) do %>
-  <focus-group direction="vertical" mnemonics retain>
-    <%= render(@overlay) do |overlay| %>
-      <% overlay.with_body(padding: :none) do %>
-        <% if @src.present? %>
-          <%= render(Primer::Alpha::IncludeFragment.new(src: @src, loading: preload? ? :eager : :lazy, "data-target": "action-menu.includeFragment")) do %>
-            <%= render(Primer::Alpha::ActionMenu::List.new(id: "#{@menu_id}-list", menu_id: @menu_id)) do |list| %>
-              <% list.with_item(
-                aria: { disabled: true },
-                content_arguments: {
-                  display: :flex,
-                  align_items: :center,
-                  justify_content: :center,
-                  text_align: :center,
-                  autofocus: true
-                }
-              ) do %>
-                <%= render Primer::Beta::Spinner.new(aria: { label: "Loading content..." }) %>
-              <% end %>
-            <% end %>
-          <% end %>
-        <% else %>
-          <%= render(@list) %>
-        <% end %>
-      <% end %>
-    <% end %>
-  </focus-group>
+  <%= render(@primary_menu) %>
 <% end %>