[FIX] sale: Some followers of moves should not be added

- Create a Deferred Revenue Model on a Current Liability account
- Create a Sale Order yourself (User 1), with Salesperson User 2
- Create the invoice from it
- Remove the salesperson from the invoice and add User 3 instead
- Change the account to the Revenue Model's one
- Post the invoice
- Post the deferred revenue created
=> User 2 is follower of the entries generated

The problem is that the context comes from the sales order, and
contains a `default_user_id` in the context.
The solution provided is to remove it from the context given, as
it serves no purpose (the invoices are already created).

opw-3141495

closes odoo/odoo#120419

Signed-off-by: Victor Feyens (vfe) <vfe@odoo.com>