Add name attribute to heading content blocks

This way we can simplify the code and don't have to rely on `.try`
statements which are confusing and so we don't allow them in the
`Rails/SafeNavigation` Rubocop rule.

app/controllers/admin/site_customization/content_blocks_controller.rb

@@ -77,7 +77,7 @@ class Admin::SiteCustomization::ContentBlocksController < Admin::SiteCustomizati
     if @content_block.is_a? Budget::ContentBlock
       @selected_content_block = "hcb_#{@content_block.heading_id}"
     else
-      @selected_content_block = @content_block.heading.name
+      @selected_content_block = @content_block.name
     end
     @is_heading_content_block = true
     render :edit

app/models/budget/content_block.rb

@@ -4,5 +4,6 @@ class Budget
     validates :heading, presence: true, uniqueness: { scope: :locale }
 
     belongs_to :heading
+    delegate :name, to: :heading, allow_nil: true
   end
 end

app/views/admin/site_customization/content_blocks/edit.html.erb

@@ -1,5 +1,5 @@
 <% provide :title do %>
-  <%= t("admin.header.title") %> - <%= t("admin.menu.site_customization.content_blocks") %> - <%= @content_block.try(:name) || @content_block.heading.try(:name) %> (<%= @content_block.locale %>)
+  <%= t("admin.header.title") %> - <%= t("admin.menu.site_customization.content_blocks") %> - <%= @content_block.name %> (<%= @content_block.locale %>)
 <% end %>
 
 <%= back_link_to admin_site_customization_content_blocks_path %>

app/views/admin/site_customization/content_blocks/index.html.erb

@@ -43,7 +43,7 @@
     <% end %>
     <% @headings_content_blocks.each do |content_block| %>
       <tr id="<%= dom_id(content_block) %>">
-        <td><%= link_to "#{content_block.heading.name} (#{content_block.locale})", admin_site_customization_edit_heading_content_block_path(content_block) %></td>
+        <td><%= link_to "#{content_block.name} (#{content_block.locale})", admin_site_customization_edit_heading_content_block_path(content_block) %></td>
         <td><%= raw content_block.body %></td>
         <td>
           <%= render Admin::TableActionsComponent.new(

spec/models/budget/content_block_spec.rb

@@ -19,4 +19,18 @@ describe Budget::ContentBlock do
                         heading: heading_content_block_en.heading, locale: "es")
     expect(valid_block).to be_valid
   end
+
+  describe "#name" do
+    it "uses the heading name" do
+      block = Budget::ContentBlock.new(heading: Budget::Heading.new(name: "Central"))
+
+      expect(block.name).to eq "Central"
+    end
+
+    it "returns nil on new records without heading" do
+      block = Budget::ContentBlock.new
+
+      expect(block.name).to be_nil
+    end
+  end
 end