[FIX] contract: Fix performance issue on contract line read + Fix contract partner label + contract company must be the same as the sale order

- multi-company record rules on contract line causes performance issue
- the label Partner (always False) don't make any sens
- When creating a contract from a sale order the company must be the sale order
  company and not the user company

contract/models/abstract_contract.py

@@ -14,12 +14,12 @@ class ContractAbstractContract(models.AbstractModel):
     _description = 'Abstract Recurring Contract'
 
     # These fields will not be synced to the contract
-    NO_SYNC = ['name', 'partner_id']
+    NO_SYNC = ['name', 'partner_id', 'company_id']
 
     name = fields.Char(required=True)
     # Needed for avoiding errors on several inherited behaviors
     partner_id = fields.Many2one(
-        comodel_name="res.partner", string="Partner (always False)", index=True
+        comodel_name="res.partner", string="Partner", index=True
     )
     pricelist_id = fields.Many2one(
         comodel_name='product.pricelist', string='Pricelist'

contract/models/contract_line.py

@@ -24,6 +24,7 @@ class ContractLine(models.Model):
         string='Contract',
         required=True,
         index=True,
+        auto_join=True,
         ondelete='cascade',
     )
     analytic_account_id = fields.Many2one(