[fix] if image load fails on client side, show default image

BTW: change icon color from red to gray

Closes:

- https://github.com/searxng/searxng/issues/4066

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/static/themes/simple/svg4web.svgo.js

@@ -14,6 +14,5 @@ module.exports = {
     'sortAttrs',
     // Optimize SVG for WEB usage
     'convertStyleToAttrs',
-    'removeXMLNS'
   ],
 };