Currently, an error occurs on clicking on the graph or the pivot cell if the data is grouped by Employee/Manager/Department.

### **Steps to reproduce**
1) Install helpdesk_timesheet with demo data
2) Go to Timesheet > Reporting > Ticket Analysis
3) Set group by to Employee
4) Click on any graph bar or pivot cell

### **Error:**
`ValueError: Invalid field helpdesk.ticket.employee_id in condition ('employee_id', '=', 1)`

Root Cause:
The `helpdesk.ticket.report.analysis` model includes specific fields such as `employee_id`, `department_id`, and `employee_parent_id` (see [1]) that are defined for reporting purposes but do not exist on the `helpdesk.ticket` model. When a user clicks a data point to view related tickets, the reporting view passes the current domain directly to the ticket list view. Because `helpdesk.ticket` lacks these fields, the ORM fails to validate the domain, resulting in a server error.

[1]- https://github.com/odoo/enterprise/blob/8d16b647431985dd7c216ae39eea6ca050e04b46/helpdesk_timesheet/report/helpdesk_ticket_report_analysis.py#L15-L17

### **Fix:**
This commit introduces a mixin to intercept the openView call. The mixin maps reporting-specific fields to valid relational paths on the ticket model `(for example, employee_id is transformed into user_id.employee_id)`. This ensures that the domain generated from the report model is compatible with the target ticket model.

**opw-5931273**

Forward-Port-Of: odoo/enterprise#108503