This update makes the Project app easier to use by repositioning an important task conflict filter where users are more likely to find it. It also adds an optional worksheet template column in shared sub-task lists, giving teams more context when reviewing field service work.

Purpose of this PR to improve generic usage of project
app.

So, in this PR done following changes:
- move 'conflict_task' filter position above 'tasks_due_today'.
- added optional field in project_sharing_view sub-task list view
   'worksheet_template_id'.

task - 2889829

This update renames UK-related localization references to GB to align with the official ISO country code standard. It helps keep country-specific reporting and payment configuration consistent with international naming conventions, with minimal expected business impact.

Rename "uk" instances to "gb" in order to respect norm ISO 3166-1 alpha-2 code

Task: 2373769

Down payment invoices now keep the same tax field behavior as the original sales order when showing TaxCloud-related tax details. This helps ensure tax breakdowns remain consistent and easier to review during invoicing.

Set attr same as parent in "tax_id" override

Task: 2678531

Payroll payslip line and worked-days line editing screens have been updated to a newer interface framework. This should help keep payroll views easier to maintain while preserving the existing payroll editing experience for users.

Converts payslip_line_one2many field.
Converts worked_days_line_one2many field.
Converts payslip_edit_lines_form view.

task-2971404

The Knowledge app removes redundant database indexing on article members. This keeps the underlying data structure simpler and can reduce unnecessary maintenance overhead without changing user-facing behavior.

- duplicate: knowledge_article_member_article_partner_idx, knowledge_article_member_unique_article_partner
- article_id unnecessary as it's covered by knowledge_article_member_unique_article_partner

The document accounting demo data now links the reconciliation request activity type to the right business model. This helps ensure reconciliation-related activities are categorized correctly and behave more consistently for users.

Task: 2963861
Signed-off-by: maximilien(malb) <malb@odoo.com>