fix(users): show locked super admin roles

[Haz3-jolt]

Purpose / Description

Admins who cannot assign the super_admin role saw super admin users as an empty role selector. This makes the users table show Super Admin and disables the picker when the current admin cannot edit that role.

Fixes

None.

Approach

• Keep the current role as the only option when it is outside the signed in admin's assignable roles.
• Disable the picker for uneditable roles so the existing disabled styling greys it out.
• Preserve the existing editable role picker for roles the admin is allowed to assign.

How Has This Been Tested?

Learning (optional, can help others)

The existing ROLE_LABELS and PickerSelect behavior already covered the display and disabled states. The fix only needed to include the current uneditable role in the picker options.

Checklist

Please, go through these checks before submitting the PR.

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas.
• You have performed a self-review of your own code.
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings).

AI Assistance

Was generative AI tooling used to co-author this PR?

• Yes(Please Specify the tool): Pi coding agent
• Was the generated code manually reviewed and tested?