[IMP] sale_timesheet: remove deprecated code in task

In 14.0, we removed the warning displayed in onchange methods. These
onchange methods were only used for this use case. Then, this commit
removes these onchange methods.

task-2424382

addons/sale_timesheet/models/project.py

@@ -252,16 +252,6 @@ class ProjectTask(models.Model):
         for task in self:
             task.remaining_hours_so = mapped_remaining_hours[task._origin.id]
 
-    @api.onchange('sale_line_id')
-    def _onchange_sale_line_id(self):
-        # TODO: remove me in master
-        return
-
-    @api.onchange('project_id')
-    def _onchange_project_id(self):
-        # TODO: remove me in master
-        return
-
     @api.depends('analytic_account_id.active')
     def _compute_analytic_account_active(self):
         super()._compute_analytic_account_active()