[FIX] account: Invoice line account updated incorrectly

Steps to reproduce the bug:

- Let's consider the customer invoice journal J with the default credit account A1
- Let's consider a customer invoice I with one line L1
- On L1 is set account A2 and product P1
- Import on I a new line L2 with account A3 and product P2

Bug:

The account of L1 was changed by A1 instead of keeping A2

opw:2230808

closes odoo/odoo#49582

X-original-commit: 115a18a1cdecdc6d76920efdf323fb91f2f408ee
Signed-off-by: Simon Goffin (sig) <sig@openerp.com>

addons/account/models/account_move.py

@@ -1584,7 +1584,7 @@ class AccountMove(models.Model):
             # Shortcut to load the demo data.
             # Doing line.account_id triggers a default_get(['account_id']) that could returns a result.
             # A section / note must not have an account_id set.
-            if not line._cache.get('account_id') and not line.display_type:
+            if not line._cache.get('account_id') and not line.display_type and not line._origin:
                 line.account_id = line._get_computed_account()
                 if not line.account_id:
                     if self.is_sale_document(include_receipts=True):