Occasionally the test_kardex_report test fails:

```
Traceback (most recent call last):
  File "/data/build/enterprise/l10n_pe_reports_stock/tests/test_ple_kardex_report.py", line 126, in test_kardex_report
    self.assertSequenceEqual(
AssertionError: Sequences differ: ['M1|[18 chars]|1||02/01/2024|01|FBILL202401|0002|02|product_[313 chars], ''] != ['M1|[18 chars]|1||01/01/2024|01|FBILL202401|0001|02|product_[313 chars], '']

First differing element 0:
'M1|0[17 chars]|1||02/01/2024|01|FBILL202401|0002|02|product_[21 chars]0|1|'
'M1|0[17 chars]|1||01/01/2024|01|FBILL202401|0001|02|product_[21 chars]0|1|'

- ['M1|0000|1|99|FURN9999|1||02/01/2024|01|FBILL202401|0002|02|product_order_no|NIU|3.00|0.00|1|',
?                             ^                           ^

+ ['M1|0000|1|99|FURN9999|1||01/01/2024|01|FBILL202401|0001|02|product_order_no|NIU|3.00|0.00|1|',
?                             ^                           ^
```

The issue was reproducible locally by disabling nested loop joins: `self.env.cr.execute("SET LOCAL enable_nestloop = off")` to nudge Postgres to use a different join strategy.

The test creates a PO that is picked and invoiced in two steps (first quantity 3, then the remaining 2). As a result, the `stock.valuation.layer` ends up being linked to two `account.move.line`s because the join goes through the same `purchase_order_line`. So it will appear twice in the `_get_ple_reports_data()` query. A `DISTINCT
ON (stock_valuation_layer.id)` was already there with the goal of picking one of them. Which one depends on the order, but it's not deterministic: the valuation layer's `id`, `product_id`, and `create_date` will all be the same.

This commit makes the behavior deterministic by sorting on PO line and SO line ids.

runbot-error-238888

Forward-Port-Of: odoo/enterprise#107047