fix(expense_claim): handle partial advance settlement in expense claims (backport #4563)

[mergify]

Reason

• Expense Claims created from Employee Advance were incorrectly marked as "Paid" even when the advance amount only partially covered the claimed amount. As a result outstanding payable amount was ignored and payment action was not available

claimReimburseBug.mov

Changes Done

• Expense Claims with partial Employee Advance coverage are now correctly marked as “Unpaid” instead of “Paid”, ensuring any remaining balance is available for reimbursement flow.

claimReimburseFix.mov

Summary by CodeRabbit

• Bug Fixes

  • Expense claim status logic corrected so claims with advances aren’t prematurely marked as paid when advances remain unsettled.

• Tests

  • Updated expense claim tests to cover advance-linked scenarios and verify is_paid behavior before and after submission.

---

This is an automatic backport of pull request #4563 done by [Mergify](https://mergify.com).

[frappe-pr-bot]

🎉 This PR is included in version 16.8.0 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀