[FIX] account: fix accounting dashboard bar graphs

The Customer Invoices and Vendor Bills bar graphs in the accounting
dashboard skip empty weeks so the following weeks will be displayed
sooner

Steps to reproduce:
1. Install Accounting
2. Go to the accounting dashboard
3. The bar graph of Customer Invoices is not correct: it ends with empty
weeks but they should be in between the data

Solution:
Choose where each query result should be by using the aggr_date to find
in which week the data is included

Problem:
The SQL query didn't return any date for empty weeks so sorting the
result by date would leave some weeks out of the bar graph

opw-2844159

closes odoo/odoo#93535

X-original-commit: 2743d8f3
Signed-off-by: Cedric Snauwaert <csn@odoo.com>
Signed-off-by: Guillaume Merlin (megu) <megu@odoo.com>