Use icons as links to edit content blocks

Just like we do with the rest of the tables in the admin section.

spec/system/admin/site_customization/content_blocks_spec.rb

@@ -2,13 +2,19 @@ require "rails_helper"
 
 describe "Admin custom content blocks", :admin do
   scenario "Index" do
-    block = create(:site_customization_content_block)
-    heading_block = create(:heading_content_block)
+    block = create(:site_customization_content_block, name: "top_links")
+    heading_block = create(:heading_content_block, heading: create(:budget_heading, name: "Reforestation"))
     visit admin_site_customization_content_blocks_path
 
-    expect(page).to have_content(block.name)
+    within "tr", text: "top_links" do
+      expect(page).to have_link "Edit"
+    end
+
+    within "tr", text: "Reforestation" do
+      expect(page).to have_link "Edit"
+    end
+
     expect(page).to have_content(block.body)
-    expect(page).to have_content(heading_block.heading.name)
     expect(page).to have_content(heading_block.body)
   end
 
@@ -73,7 +79,7 @@ describe "Admin custom content blocks", :admin do
         click_link "Custom content blocks"
       end
 
-      click_link "top_links (en)"
+      within("tr", text: "top_links (en)") { click_link "Edit" }
 
       fill_in "site_customization_content_block_body", with: "Some other custom content"
       click_button "Update Custom content block"