Currently, a user error occurs when confirming a Sales Order (SO).

**Steps to reproduce:**

1) Install sale_project
2) Create a service product that generates a project and a task. 
3) Add a project template by creating one from the product form view. 
4) Create an SO by creating a customer with a company 
5) Add the above-created service product and confirm the SO.

**Error:**
A user exception will be triggered
```
The project and the associated partner must be linked to the same company.
```

**Cause:**

- When a project template is created from the product view, 
both the customer and the company_id default to empty.

- Later, when confirming a SO with a customer that belongs to a company, 
the new project's company_id is taken from the project template, which is empty.

https://github.com/odoo/odoo/blob/876e9d5e9ba87fa69188b2da098eec78f77040f5/addons/sale_project/models/sale_order.py#L140-L141

- However, the project’s partner_id (the customer) does have a company_id,
(since the customer value for the project will be set through SO's customer).

- This leads to a mismatch between the project’s company_id(which is empty) 
and its partner’s company_id. So a user exception will be triggered from the below lines

https://github.com/odoo/odoo/blob/876e9d5e9ba87fa69188b2da098eec78f77040f5/addons/project/models/project_project.py#L257-L258

**Solution:**

- If the project template has no company_id, and the customer of the project has one, 
set the project’s company_id to match that of the customer.

opw-4900741,4880495

Forward-Port-Of: odoo/odoo#216582