Theming: Jscolor fails on javascript unsafe eval

[rullzer]

For: https://github.com/orgs/nextcloud/projects/18

It seems the js color lib we use for the theming settings page wants to use eval. This prevents a stricter CSP

[rullzer]

@juliushaertl

[nextcloud-bot]

GitMate.io thinks possibly related issues are #5663 (Custom JS in theme failing: 'unsafe-eval'), #11029 (Contacts menu uses javascript eval), #1185 (Get rid of all unsafe-eval Javascripts), #5879 (Updater fails updating themeing), and #9851 (Upload the logo in Theming App failed).