Fix media proxy RedisLocks auto-releasing too fast (mastodon#16291)

Follow-up to mastodon#16276

app/controllers/media_proxy_controller.rb

@@ -45,7 +45,7 @@ def version
  end
 
  def lock_options
- { redis: Redis.current, key: "media_download:#{params[:id]}" }
+ { redis: Redis.current, key: "media_download:#{params[:id]}", autorelease: 15.minutes.seconds }
  end
 
  def reject_media?