[FIX] project: Creating project via service product deletes contact's data

Steps to reproduce the bug:

- Let's consider a customer C1 with email address A1 and phone P1
- Let's consider a project PR with C1 as customer
- Let's consider a service product P with:
   - Milestones (manually set quantities on order) as Service Invoicing Policy
   - Create a new project but no task as service tracking
   - PR as project template
- Create a sale order SO with C2 as customer with A2 as email address and P2 as phone
- Confirm the SO

 Bug:

 The email address and phone of C2 were changed into A1 and P1 instead of keeping A2 and P2

 opw:2439459

closes odoo/odoo#66709

X-original-commit: 1c23eba5ab4dc4108ef6209ebc529ab363c3cc6b
Signed-off-by: Simon Goffin (sig) <sig@openerp.com>