fix: ensure fresh grand_total_diff is used for each calculation [frappe]

From: https://github.com/frappe/erpnext/commit/b3fdef8d19ebb919d496b2f1e6a55706bad34f74
Date: 2025-12-11 17:48:37+05:30
By: Sagar Vora

fix: ensure fresh grand_total_diff is used for each calculation

This is a commit that is not part of any pull request.

---

Checkout instructions

# Checkout locally
git fetch upstream
git switch ft-commit-b3fdef8d19ebb9

# Alternatively, re-take the changes
git switch develop
ft take ft-commit-b3fdef8d19ebb9

# 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