Merge pull request #306 from torchbox/fix/animation-glitch

fix glitch with animation of wagtail bird's head

Author: helenb

tbx/project_styleguide/templates/patterns/atoms/sprites/sprites.html

@@ -113,7 +113,7 @@
 
     {# for animated wagtail icon - head outline #}
     <symbol id="wagtail-head-outline" viewBox="0 0 80 80">
-        <g style="mix-blend-mode:screen">
+        <g>
             <path d="M49.637 15.035l2.584-4.586C36.2 1.539 25.304 11.977 21.858 18.31L7 43.86v28.826h49.743c7.106-16.378 5.168-26.86-3.23-34.067-6.719-5.765-16.581-5.022-20.673-3.93-1.938-1.529-3.386-8.69 0-14.413 4.652-7.862 13.136-6.77 16.797-5.241z" stroke="var(--color--accent-three)" stroke-width="2" stroke-linejoin="round" fill="none"/>
             <ellipse cx="53.513" cy="24.035" rx="2.584" ry="2.621" fill="var(--color--white)"/>
         </g>