This update refines the Point of Sale interface with cleaner cart spacing, better text alignment, clearer category colors in demo data, and a more adaptable Order button. It also prevents accidental course deselection in restaurant workflows, helping staff use the POS more reliably during service.

After this PR:
- Reduced extra spacing above and below the note in order lines in the cart.
- Aligned product category text with the product name.
- Prevented users from unselecting a selected course by clicking on it again.
- Ensured category buttons in POS always have different colors for demo data.
- Made the "Order" button more flexible to display the selected category.

Task: 4637174

This update adds a clearer interface for viewing and managing user groups and access rights. It helps administrators understand inherited permissions, choose the highest applicable access level automatically, and quickly find users linked to a group.

Progress of the task concerning the group (implied, UI...), following feedback

sub-task of task-4341594