[FIX] account: rule error when creating an invoice from the Documents app

Steps to reproduce:
- Install Odoo with demo data
- Go to Documents app
- Finance workspace
- Select a demo pdf
- Create invoice
- Error because of 'Mail Compose Message Rule'

The fix removes a non-necessary line when creating an invoice from a pdf

closes odoo/odoo#108989

X-original-commit: 60fbcaff
Signed-off-by: Nicolas Viseur (vin) <vin@odoo.com>
Signed-off-by: Ricardo Gomes Rodrigues (rigr) <rigr@odoo.com>