fix(plugins/core): disable css optimization for extras_css (#756) [skip ci]

source/templates/classic/image.svg

@@ -2,6 +2,7 @@
 
   <defs><style><%= fonts %></style></defs>
   <style data-optimizable="true"><%= style %></style>
+  <style><%= extras.css %></style>
 
   <foreignObject x="0" y="0" width="100%" height="100%">
     <div xmlns="http://www.w3.org/1999/xhtml" xmlns:xlink="http://www.w3.org/1999/xlink" class="items-wrapper">

source/templates/repository/image.svg

@@ -2,9 +2,8 @@
 
   <defs><style><%= fonts %></style></defs>
 
-  <style data-optimizable="true">
-    <%= style %>
-  </style>
+  <style data-optimizable="true"><%= style %></style>
+  <style><%= extras.css %></style>
 
   <foreignObject x="0" y="0" width="100%" height="100%">
     <div xmlns="http://www.w3.org/1999/xhtml" xmlns:xlink="http://www.w3.org/1999/xlink">

source/templates/terminal/image.svg

@@ -28,6 +28,7 @@
         <% } %>
       <% } %>
   </style>
+  <style><%= extras.css %></style>
 
   <foreignObject x="0" y="0" width="100%" height="100%">
     <div xmlns="http://www.w3.org/1999/xhtml" xmlns:xlink="http://www.w3.org/1999/xlink">