feat(Feedback): Update feedback tokens

What does this MR do?

• Update feedback strong design tokens to align with design direction.
• Use feedback strong tokens for the toast.

Note: It's intentional to use the same colors for both light and dark mode. Also, the neutral used aligns with changes in !4592 (merged) and !4593 (merged).

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Integration merge requests

• GitLab: mr_url
• CustomersDot: mr_url
• Status Page: mr_url

Does this MR meet the acceptance criteria?

This checklist encourages the authors, reviewers, and maintainers of merge requests (MRs) to confirm changes were analyzed for conformity with the project's guidelines, security and accessibility.

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Conformity

• Code review guidelines.
• GitLab UI's contributing guidelines.
• 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 (see integration merge requests above).
• Added the ~"component:*" label(s) if applicable.

Related to #2733 (closed)