fix: show specific error when Payable/Bank-Cash Account missing on Ex…

[reachsanjivbhagat-gif]

Fixes #4152

Problem

When submitting an Expense Claim with a missing Payable Account (or a Mode of Payment without a configured Bank/Cash account when "Is Paid" is checked), the system raised a generic, low-level error ("Account is required") from GL Entry validation. Since Expense Claim has multiple account-related fields (Payable Account, Bank/Cash Account), this didn't tell the user which field actually needed to be set.

Fix

Added two explicit checks in validate_account_details() on Expense Claim, which already runs before GL entries are built in get_gl_entries():

• If the claim has a grand_total and no payable_account is set, throw a clear error naming the Payable Account field.
• If is_paid is checked and the account resolved via get_bank_cash_account(mode_of_payment, company) is empty, throw a clear error naming the Bank/Cash Account and the selected Mode of Payment.
  Both checks are purely additive validation - no existing behavior changes for claims that already have valid accounts configured.

Testing

Verified by reading through get_gl_entries() / make_gl_entries() to confirm validate_account_details() runs before the GL entry dicts are constructed, so the new checks fire before the previous generic error could occur.

[greptile-apps]

Confidence Score: 5/5

Safe to merge — purely additive validation with no behavior change for well-configured claims.

The two new checks only throw earlier with a clearer message in cases that previously failed anyway with a generic error. No existing code paths are altered for valid data.

No files require special attention.

_{Reviews (3): Last reviewed commit: "perf: avoid duplicate get_bank_cash_acco..." | Re-trigger Greptile}