fix(es_extended): remove admin fallback for superadmin group

[Kenshiin13]

Description

This PR removes the hardcoded behavior that automatically converted the “superadmin” group to “admin.” From now on, “superadmin” is treated as a valid group on its own. Opinionated logic like this has no place in a framework — developers should have full control over how their permission groups are defined and used.

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Motivation

ESX previously forced “superadmin” to fall back to “admin,” removing flexibility and making it harder for server owners to structure permissions their own way. A framework should never enforce arbitrary conventions or override developer intent. This change ensures group handling is neutral, predictable, and fully customizable.

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PR Checklist

• My commit messages and PR title follow the Conventional Commits standard.
• My changes have been tested locally and function as expected.
• My PR does not introduce any breaking changes.
• I have provided a clear explanation of what my PR does, including the reasoning behind the changes and any relevant context.

[CLAassistant]

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