Remove duplication in group switcher component

We can extract a method to reduce the amount of ERB code and remove the
duplication in the link texts. We also make the list consistent; now we
always use a <strong> tag in the group name, no matter whether there are
many groups or only one.

app/components/admin/budgets_wizard/headings/group_switcher_component.html.erb

@@ -2,21 +2,10 @@
   <% if other_groups.one? %>
     <p>
       <%= currently_showing_text %>
-      <%= link_to t("admin.budget_headings.group_switcher.the_other_group", group: other_groups.first.name),
-                  headings_path(other_groups.first) %>
+      <%= link_to_group(other_groups.first) %>
     </p>
   <% else %>
     <p><%= currently_showing_text %></p>
-    <ul>
-      <% other_groups.each do |other_group| %>
-        <li>
-          <%= link_to sanitize(t(
-                        "admin.budget_headings.group_switcher.the_other_group",
-                        group: tag.strong(other_group.name)
-                      )),
-                      headings_path(other_group) %>
-        </li>
-      <% end %>
-    </ul>
+    <%= link_list(*other_groups.map { |group| link_to_group(group) }) %>
   <% end %>
 </div>

app/components/admin/budgets_wizard/headings/group_switcher_component.rb

@@ -1,5 +1,6 @@
 class Admin::BudgetsWizard::Headings::GroupSwitcherComponent < ApplicationComponent
   attr_reader :group
+  use_helpers :link_list
 
   def initialize(group)
     @group = group
@@ -26,4 +27,12 @@ class Admin::BudgetsWizard::Headings::GroupSwitcherComponent < ApplicationCompon
     def currently_showing_text
       sanitize(t("admin.budget_headings.group_switcher.currently_showing", group: group.name))
     end
+
+    def link_to_group(group)
+      link_to(link_to_group_text(group), headings_path(group))
+    end
+
+    def link_to_group_text(group)
+      sanitize(t("admin.budget_headings.group_switcher.the_other_group", group: tag.strong(group.name)))
+    end
 end