fix: Previous document currency getting overridden

[deepeshgarg007]

Issue: Document Currency from Purchase Receipt gets overridden in Purchase Invoice

Steps to replicate

1. Make sure the supplier you are using doesn't have a default currency set
2. Make a purchase receipt in currency other than Company currency
3. Make a Purchase Invoice from the receipt using the "Create Invoice" button, make sure the currency in Purchase Receipt is mapped in Purchase Invoice

[deepeshgarg007]

@Mergifyio backport develop

[mergify]

backport develop

✅ Backports have been created

• #29434 fix: Previous document currency getting overridden (backport #29404) has been created for branch develop