Render header on sdg index page

We no longer show the static header when we have created a
custom header.

app/components/sdg/goals/index_component.html.erb

@@ -1,9 +1,13 @@
 <% provide(:title) { title } %>
 
 <main class="sdg-goals-index">
-  <header class="section-header">
-    <h1><%= title %></h1>
-  </header>
+  <% if header.present? %>
+    <%= render "shared/header", header: header %>
+  <% else %>
+    <header class="section-header">
+      <h1><%= title %></h1>
+    </header>
+  <% end %>
 
   <%= render Shared::BannerComponent.new("sdg") %>
 

app/components/sdg/goals/index_component.rb

@@ -1,9 +1,10 @@
 class SDG::Goals::IndexComponent < ApplicationComponent
-  attr_reader :goals, :phases
+  attr_reader :goals, :header, :phases
   delegate :link_list, to: :helpers
 
-  def initialize(goals, phases)
+  def initialize(goals, header:, phases:)
     @goals = goals
+    @header = header
     @phases = phases
   end