feat(GlTokenSelector): allow data category props to be passed to token

What does this MR do?

A supporting merge for: gitlab#262857 (comment 454382389) inside Category:Incident Management where we need the ability to allow tokens to follow the Pajamas design system for category based data colors i.e. cheveron skipping palette. This merge allows for that to be built into the tokens through two props that can dynamically generate the right mixin.

Does this MR meet the acceptance criteria?

Conformity

• Code review guidelines.
• [-] GitLab UI's contributing guidlines.
• [-] If it changes a Pajamas-compliant component's look & feel, the MR has been reviewed by a UX designer.
• [-] If it changes GitLab UI's documentation guidelines, the MR has been reviewed by a Technical Writer.
• [-] If the MR changes a component's API, integration MR(s) have been opened in the following projects to ensure that the @gitlab/ui package can be upgraded quickly after the changes are released:
  • [-] GitLab: mr_url
  • [-] CustomersDot: mr_url
  • [-] Status Page: mr_url
• Added the ~"component:*" label(s) if applicable.

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] Security reports checked/validated by a reviewer from the AppSec team