chore: fix dark theme config in Angular dev app

[sis0k0]

PR Checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• If applicable, have a visual design approval

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• clarity.design website / infrastructure changes
• Other... Please describe:

What is the current behavior?

Starting the dev app in dark mode (yarn serve:dark) fails with:

Error: ../icons/src/clr-icons.scss
Module build failed (from ./node_modules/mini-css-extract-plugin/dist/loader.js):
ModuleError: Module Error (from ./node_modules/@angular-devkit/build-angular/node_modules/postcss-loader/dist/cjs.js):
Loading PostCSS "" parser failed: The argument 'id' must be a non-empty string. Received ''

Issue Number: N/A

What is the new behavior?

Starting the dev app in dark mode works fine. Thanks, @bdryanovski for providing the solution!

Does this PR introduce a breaking change?

• Yes
• No