[TB] Implement color deletion capability

[aaronreed708]

Problem/Concern

The outcome from this issue is giving users the ability to delete colors from the color palette per the design for #820. This will include implementing:

• A mechanism for identifying what parts of the design system will be impacted by the deletion
• UI for selecting new values for the impacted parts of the design system

Proposed Solution

Implement the wireframe: https://www.figma.com/design/Co8gYdDmE64Wv90eWy9FwE/Mentorship---Edit-Theme-Builder-Colors-and-Themes?node-id=218-23574&t=E5PcLhRG9eQhu8VC-4