fix sale report: left join on res partner category'
fix sale report: left join on res partner category'

The join statement restricts some sales in the report view:
```
join res_partner_res_partner_category_rel pcr
  on (pcr.partner_id=s.partner_id)
```

https://gestion.coopiteasy.be/web#id=23&view_type=form&model=project.task&action=475&active_id=2

houssine78/addons,houssine78/addons,houssine78/addons