fix(Account): Pass parent currency to child currency

In a scenario where Parent Company Account's Currency is different
from it's default currency, the Account Currency of Child would be set
from the default currency of Company which might be wrong

erpnext/accounts/doctype/account/account.py

@@ -123,7 +123,9 @@ class Account(NestedSet):
 				doc.flags.ignore_root_company_validation = True
 				doc.update({
 					"company": company,
-					"account_currency": None,
+					# parent account's currency should be passed down to child account's curreny
+					# if it is None, it picks it up from default company currency, which might be unintended
+					"account_currency": self.account_currency,
 					"parent_account": parent_acc_name_map[company]
 				})
 				doc.save()