Fix typo in about page (#13038)

config/locales/en.yml

@@ -39,7 +39,7 @@ en:
     unavailable_content_description:
       domain: Server
       reason: Reason
-      rejecting_media: 'Media files from these servers will not be processed or stored, and and no thumbnails will be displayed, requiring manual click-through to the original file:'
+      rejecting_media: 'Media files from these servers will not be processed or stored, and no thumbnails will be displayed, requiring manual click-through to the original file:'
       silenced: 'Posts from these servers will be hidden in public timelines and conversations, and no notifications will be generated from their users'' interactions, unless you are following them:'
       suspended: 'No data from these servers will be processed, stored or exchanged, making any interaction or communication with users from these servers impossible:'
     unavailable_content_html: Mastodon generally allows you to view content from and interact with users from any other server in the fediverse. These are the exceptions that have been made on this particular server.