[FIX] sale: improve compute expected date performance

Without this patch, each time the compute reaches the line with `.filtered()`, it needs a new fetch from the database. With too many sale orders, this becomes a bottleneck.

Now, before getting to that line, Odoo knows that it'll need all sale.order.line records, so it can fetch them all at once.

In a production database, loading the sale.order list goes down from 7s to 500ms with this patch.

@Tecnativa TT30390

closes odoo/odoo#72141

X-original-commit: 7969a052a19f3572e4819d163f969ae02bc8a80e
Signed-off-by: Nicolas Lempereur (nle) <nle@odoo.com>

addons/sale/models/sale_order.py

@@ -316,6 +316,7 @@ class SaleOrder(models.Model):
         """ For service and consumable, we only take the min dates. This method is extended in sale_stock to
             take the picking_policy of SO into account.
         """
+        self.mapped("order_line")  # Prefetch indication
         for order in self:
             dates_list = []
             for line in order.order_line.filtered(lambda x: x.state != 'cancel' and not x._is_delivery() and not x.display_type):