[FIX] account_financial_report: optimize computation of analytic accounts

Installing the module in a big DB was very slow.

I applied several optimizations to the method for working better with big datasets:
- Prefetch all analytic account distribution.
- Batch writes as much as possible.

@moduon MT-4982

account_financial_report/models/account_move_line.py

@@ -1,5 +1,7 @@
 # Copyright 2019 ACSONE SA/NV (<http://acsone.eu>)
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).-
+from collections import defaultdict
+
 from odoo import api, fields, models
 
 
@@ -12,24 +14,26 @@ class AccountMoveLine(models.Model):
 
     @api.depends("analytic_distribution")
     def _compute_analytic_account_ids(self):
-        for record in self:
+        # Prefetch all involved analytic accounts
-            if not record.analytic_distribution:
+        with_distribution = self.filtered("analytic_distribution")
-                record.analytic_account_ids = False
+        batch_by_analytic_account = defaultdict(list)
-            else:
+        for record in with_distribution:
-                record.update(
+            for account_id in map(int, record.analytic_distribution):
-                    {
+                batch_by_analytic_account[account_id].append(record.id)
-                        "analytic_account_ids": [
+        existing_account_ids = set(
-                            (
+            self.env["account.analytic.account"]
-                                6,
+            .browse(map(int, batch_by_analytic_account))
-                                0,
+            .exists()
-                                self.env["account.analytic.account"]
+            .ids
-                                .browse([int(k) for k in record.analytic_distribution])
+        )
-                                .exists()
+        # Store them
-                                .ids,
+        self.analytic_account_ids = False
-                            )
+        for account_id, record_ids in batch_by_analytic_account.items():
-                        ]
+            if account_id not in existing_account_ids:
-                    }
+                continue
-                )
+            self.browse(record_ids).analytic_account_ids = [
+                fields.Command.link(account_id)
+            ]
 
     def init(self):
         """