Rework stock item form modal

Since the modal open and closes on the current page, close links are
not needed anymore. Same goes for the explicit q and page params.

The `Cancel` button is simplified to use dialog standards.

admin/app/components/solidus_admin/stock_items/edit/component.html.erb

@@ -3,7 +3,7 @@
   data-<%= stimulus_id %>-initial-count-on-hand-value="<%= @stock_item.count_on_hand_was || @stock_item.count_on_hand %>"
   data-action="input-><%= stimulus_id %>#updateCountOnHand"
 >
-  <%= render component("ui/modal").new(title: t(".title"), close_path: solidus_admin.stock_items_path(page: params[:page], q: permitted_query_params)) do |modal| %>
+  <%= render component("ui/modal").new(title: t(".title")) do |modal| %>
     <%= form_for @stock_item, url: solidus_admin.stock_item_path(@stock_item), html: { id: form_id } do |f| %>
       <div class="flex flex-col gap-6 pb-4">
         <div class="flex gap-4">
@@ -58,24 +58,16 @@
           checked: f.object.backorderable?,
           include_hidden: true,
         ) %>
-
-        <% if params[:q] %>
-          <%= f.hidden_field :q, value: params[:q].to_json, id: false %>
-        <% end %>
-
-        <% if params[:page] %>
-          <%= f.hidden_field :page, value: params[:page], id: false %>
-        <% end %>
       </div>
     <% end %>
 
     <% modal.with_actions do %>
-      <%= render component("ui/button").new(
-        tag: :a,
-        scheme: :secondary,
-        text: t(".cancel"),
-        href: solidus_admin.stock_items_path(page: params[:page], q: params[:q]),
-      ) %>
+      <form method="dialog">
+        <%= render component("ui/button").new(
+          scheme: :secondary,
+          text: t(".cancel"),
+        ) %>
+      </form>
 
       <%= render component("ui/button").new(
         tag: :button,