Resolve "Multiple color condition broken after page reloaded"

Every color in the conditional_color value provider needs to have a uid. When adding a new color, the web-frontend generates a unique uid that added to the object. This is required for updating the value provider (reordering, changing color, etc). The backend did not accept the uid, so after you reload the page it's gone.

Because the backend doesn't need this uid at all, I've decided to fix this problem by adding a unique uid every time a decoration value provider is populated. This makes sure that when the page loads initially, it has a uid and when a new one is added as well.

How to test

• Add a background color decorator.
• Add two colors.
• Reload the page.
• It should be possible to change both colors.
• It should be possible to reorder.

Merge Request Checklist

• changelog.md has been updated if required
• New/updated Premium features are separated correctly in the premium folder
• The latest Chrome and Firefox have been used to test any new frontend features
• Documentation has been updated
• Quality Standards are met
• Performance: tables are still fast with 100k+ rows, 100+ field tables
• The redoc API pages have been updated for any REST API changes
• Our custom API docs are updated for changes to endpoints accessed via api tokens
• The UI/UX has been updated following UI Style Guide

Closes #1140 (closed)