fix: set rate for PO created against BO (backport #39765) (#39767)
* fix: set rate for PO created against BO
(cherry picked from commit 0e5b4e5f07)
# Conflicts:
# erpnext/manufacturing/doctype/blanket_order/blanket_order.py
* chore: `conflicts`
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Co-authored-by: s-aga-r <sagarsharma.s312@gmail.com>
(cherry picked from commit 22138867f5)
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>