Add k8s_proxy scope description for PrAT and align for PAT

What does this MR do and why?

This change set fixes the k8s_proxy scope description for Project Access Tokens and uses a more descriptive one for PAT (aligned with PrAT and GAT).

It has been introduced in Add k8s_proxy_pat feature flag (!129661 - merged)

Relates Add new k8s_proxy scope for PATs (#422408 - closed)

Screenshots or screen recordings

For PAT:

Before	After

For PrAT / GAT:

Before	After

MR acceptance checklist

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