icons are not displayed when using a prefix

[Neor5804]

Hello everybody!

Faced the problem of displaying icons if a prefix is used. my docker-compose.yml file:

...
  environment:
      - "RAILS_RELATIVE_URL_ROOT=/fluentd"
...

I'm using the current master: $ git log

commit a4883e7d17e17bb9ec1f4b9cc730f604e79ba1c3 (HEAD -> master, origin/master, origin/HEAD)
Merge: 9e4a92d 2d03328
Author: Kentaro Hayashi <[email protected]>
Date:   Fri Aug 13 18:17:39 2021 +0900

    Merge pull request #379 from fluent/dependabot/npm_and_yarn/url-parse-1.5.3
    
    Bump url-parse from 1.5.1 to 1.5.3