The framework ignores `no_copy` while amending, so a reconciled voucher
carried a stale clearance date into its amendment even though the linked
bank transaction gets unreconciled on cancellation. Reset it via a shared
`before_insert` hook on AccountsController.
Fixes#54909
(cherry picked from commit 1a8d73cbbe)
# Conflicts:
# erpnext/controllers/accounts_controller.py