Merge branch 'aregnery/learn-gitlab-svg-change-to-bulb' into 'master'

Update Learn GitLab icon in navigation to bulb

See merge request gitlab-org/gitlab!83421

app/assets/images/learn_gitlab/graduation_hat.svg

-<svg width="16" height="17" xmlns="http://www.w3.org/2000/svg"><path fill="#fffff" d="M1.53 7.639l-.476.88.476-.88zm0-1.758L1.054 5l.476.88zm2.257 2.982h1v-.596l-.523-.283-.477.879zm8.424 0l-.476-.88-.524.284v.596h1zm2.257-1.224l.477.88-.477-.88zm0-1.758l-.476.879.476-.88zM8.476 2.632l-.477.88.477-.88zm-.953 0l.476.88-.476-.88zM2.007 6.76l-.953-1.758c-1.396.756-1.396 2.76 0 3.516l.953-1.758zm2.257 1.224L2.007 6.76l-.953 1.758L3.31 9.742l.953-1.758zm.523 1.995V8.863h-2v1.116h2zM8 12.5c-1.949 0-3.212-1.289-3.212-2.52h-2c0 2.656 2.51 4.52 5.212 4.52v-2zm3.212-2.52c0 1.231-1.262 2.52-3.212 2.52v2c2.704 0 5.212-1.864 5.212-4.52h-2zm0-1.117v1.116h2V8.863h-2zm2.78-2.103l-2.256 1.223.953 1.759 2.257-1.224-.953-1.758zm0 0l.954 1.758c1.396-.757 1.396-2.76 0-3.516l-.953 1.758zM8 3.51l5.993 3.249.953-1.758-5.993-3.249L8 3.511zm0 0l.953-1.758a2 2 0 00-1.906 0L8 3.511zM2.007 6.76l5.992-3.25-.953-1.758-5.992 3.249.953 1.758z"/><path fill="#fffff" d="M7.228 7.541c-.187-.112-.277-.427-.201-.704.076-.276.288-.41.475-.297L11 8.644v5.316c0 .298-.163.54-.365.54-.2 0-.364-.242-.364-.54V9.37L7.228 7.54z"/></svg>
\ No newline at end of file

lib/sidebars/projects/menus/learn_gitlab_menu.rb

@@ -45,9 +45,9 @@ module Sidebars
           }
         end
 
-        override :image_path
-        def image_path
-          'learn_gitlab/graduation_hat.svg'
+        override :sprite_icon
+        def sprite_icon
+          'bulb'
         end
 
         override :render?