HR and contract screens now hide Belgian-specific employee and contract fields unless the active company is based in Belgium. This keeps forms and reports cleaner for companies in other countries and reduces confusion from irrelevant local compliance fields.

Hide fields related to belgian localisation when not using a belgian
company.

Task Id: 2496597

This change improves the notification preview in Odoo's systray so users can see rating activity and status changes instead of empty entries. It makes alerts more informative at a glance, helping users understand recent updates without opening each record.

Description of the issue/feature this PR addresses:
https://github.com/odoo-dev/odoo/tree/master-rating-tracking-change-preview-zel
Current behavior before PR:
The rate and status change is shown as empty on the systray.
Desired behavior after PR is merged:
1. Once gets rated, there will be a preview on the systray as a notification.
2. The status change will get displayed now on the systray and the tracking values become an object rather than an array.
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Payroll and HR contract screens now hide country-specific fields when they do not apply to the selected company. This keeps Belgian, French, and Indian payroll information out of views for companies in other countries, reducing clutter and helping users focus on relevant data.

Hide fields related to belgian payroll localisation when using a non
belgian company.

Task Id: 2496597

Spreadsheet pivot data now reuses model information more efficiently instead of repeatedly requesting the same details. This reduces unnecessary server calls, which should make opening spreadsheet templates smoother and lighter on system resources.