Handle close vault - Githubissues

Description

This issue tracks the implementation of handling the closing of a vault in the Vault module.

[ ] Implement the CloseVault function and ensure the user can only close vaults that don't have any remaining debt
[ ] Ensure the function correctly updates the vault status to closed.
[ ] Update any related balances and records in the system.
[ ] Write unit tests for the CloseVault function.
[ ] Write integration tests to verify the correct behavior of vault closing.