Fix vulnerability severity badge rendering

Fixes #519618 (closed)

What does this MR do and why?

This MR targets Create a GraphQL query to get severity override... (!180849 - merged).

Refactors the severity badge component to:

1. Render severity overrides only when FF is enabled
2. Accept only last severity override information

This was done to fix an issue for vulnerability details page where only latest severity override information is available: !180858 (merged)

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Screenshots or screen recordings

Vulnerability Dashboard - No visual changes

Vulnerability Dashboard (Before)	Vulnerability Dashboard (After)

Vulnerability Details Page - Severity Information was missing

Vulnerability Details Page (Before)	Vulnerability Details Page (After)

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