[BUG]: UI /API Users with no admin privileges can no longer login

[IuliaGaitan]

🐞 Bug Summary

Users with no admin privileges can no longer login

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🧩 Affected Component

Select the area of the project impacted:

• mcpgateway - API
• mcpgateway - UI (admin panel)
• mcpgateway.wrapper - stdio wrapper
• Federation or Transports
• CLI, Makefiles, or shell scripts
• Container setup (Docker/Podman/Compose)
• Other (explain below)

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🔁 Steps to Reproduce

1. Go to http://localhost:8000/admin/login
2. Add an user email and password
3. Click Sign In

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🤔 Results

Users with no admin privileges can no longer login

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🤔 Expected Behavior

User should have the option to login and the user menu should be loaded successfully.

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📓 Logs / Error Output

Paste any relevant stack traces or logs here.
⚠️ Do not paste secrets, credentials, or tokens.

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🧠 Environment Info

You can retrieve most of this from the /version endpoint.

Key	Value
Version or commit	v0.128.0
Runtime	Python 3.12.3
Platform / OS	Linux 6.6.87.2-microsoft-standard-WSL2 (x86_64)
Container	none

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🧩 Additional Context (optional)

Related to #2390