Fix variabel for client id in config.js

[jepp3]

When starting the ui container, a env variabel is replaced in the config.js at startup. The env variabel will not exist during local development. Maybe think out a good way to handle this, without having to modify config.js. The reason for this is that its easy to commit the change to the file. One could add it to gitignore? And force add it changes to the file is required. Maybe @magnusp has some insight in this.