fix: ensure that additional discount amount is not mapped repeatedly by sagarvora [frappe] PR#50155

From: https://github.com/frappe/erpnext/pull/50155
Date: 2025-10-18 00:08:38+05:30

• chore: remove unused import
• refactor: simplify logic
• fix: handle returns as well
• test: some tests to ensure correct discount mapping
• fix: validate that discount amount cannot exceed total before discount
• fix: ensure that additional discount amount is not mapped repeatedly

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Checkout instructions

# Checkout locally
git fetch upstream
git switch ft-pr-50155

# Alternatively, re-take the changes
git switch develop
ft take ft-pr-50155

# Make changes then rebase
git rebase -i develop

# Fix or ignore conflicts
git checkout --theirs .
git rebase --continue

# Force-push changes
git push --force-with-lease