Add unit tests for the contract rejecting any call from a wallet that has been blacklisted by the admin

[Chucks1093]

Summary

The admin can blacklist a wallet address to block it from buying, selling, or registering as a creator. Unit tests should confirm blacklisted wallets are rejected across all mutating functions and that removing the wallet from the blacklist restores access.

Scope

• Blacklist a wallet and attempt a buy — assert it panics with wallet_blacklisted
• Blacklist a wallet and attempt a sell — assert it panics with wallet_blacklisted
• Blacklist a wallet and attempt creator registration — assert it panics with wallet_blacklisted
• Remove the wallet from the blacklist and assert a buy succeeds
• Assert a non-admin wallet cannot add or remove addresses from the blacklist

Acceptance Criteria

• Blacklisted wallet panics with wallet_blacklisted on buy
• Blacklisted wallet panics with wallet_blacklisted on sell
• Blacklisted wallet panics with wallet_blacklisted on registration
• Removing from blacklist restores full access
• Non-admin cannot modify the blacklist

ETA: 12 hours

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Coordinate on Telegram

[salazarsebas]

Hello Accessly Team,

My background

My name is Sebastián, and I'm a founder of Acachete Labs 💻.
I'm confident about the opportunity to contribute to your Stellar-based project and specifically to this issue. ☑

Experience

I'm a full-stack developer with solid experience in blockchain and Web3 technologies, particularly in projects involving smart contracts and decentralized solutions.
I have worked on several projects mainly based on Stellar, and I'm ready to apply that knowledge here.

I am motivated by the opportunity to improve my skills while delivering real value to the project.

Links

You can find my profiles and links here:

GitHub: https://github.com/salazarsebas
LinkedIn: https://www.linkedin.com/in/sebastian-salazar-solano/

Thank you for considering my contribution. I'm excited to work on this issue and create a positive impact. Please let me know if you have any questions or need additional information.

Best regards,
Sebastián

[akintewe]

I've been creating intricate forms and e-commerce systems for more than four years as a full-stack developer. I have designed inventory management systems for agricultural enterprises and have experience with image processing and large-scale state management. I have also worked on this project in the past.
My ETA is one hour, and I would love to work on this problem.

[grantfox-oss]

🦊 GrantFox — @akintewe has been assigned to this issue as part of the Third Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #700)
2. Your PR will be reviewed by the accesslayerorg maintainers

Good luck! Track your progress on GrantFox.