Add tests covering limit-change authorization

[arisu6804]

Summary

Add tests covering limit-change authorization.

Context

Tracking issue for the RemitFlow smart contract. Open to contributors.

Acceptance criteria

• Implement the change described above
• Add or update automated tests
• Update the relevant documentation

[funds0033-cmyk]

i will like to work on this

[grantfox-oss]

🦊 GrantFox — @funds0033-cmyk has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #95)
2. Your PR will be reviewed by the RemitFlow maintainers

Good luck! Track your progress on GrantFox.