UX: Add login button icon to no_ember page (#7982)

lib/svg_sprite/svg_sprite.rb

@@ -303,6 +303,19 @@ License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL
     false
   end
 
+  # For use in no_ember .html.erb layouts
+  def self.raw_svg(name)
+    get_set_cache("raw_svg_#{name}") do
+      symbol = search(name)
+      break "" unless symbol
+      symbol = Nokogiri::XML(symbol).children.first
+      symbol.name = "svg"
+      <<~HTML
+        <svg class="fa d-icon svg-icon svg-node" aria-hidden="true">#{symbol}</svg>
+      HTML
+    end.html_safe
+  end
+
   def self.theme_sprite_variable_name
     THEME_SPRITE_VAR_NAME
   end