[FIX] mrp: real duration

- Create a MO which generates WOs
- User 1 starts working on it
- User 2 starts working on it

The field 'Real Duration' only displays the time spent by the user
connected. It means that there will be an inconsistency between the
field 'Real Duration' and the list of durations shown in the `time_ids`
field.

We want to keep 'Real Duration' limited to the current user, because it
should represent the duration updated in real time (done in widget
`mrp_time_counter`). However, we also want to see the total real
drations for all users. Thereofe, we simply update the view to show the
total in the list view.

opw-784456

addons/mrp/views/mrp_workorder_views.xml

@@ -201,7 +201,7 @@
                             <tree>
                                 <field name="date_start"/>
                                 <field name="date_end"/>
-                                <field name="duration" widget="float_time"/>
+                                <field name="duration" widget="float_time" sum="Total duration"/>
                                 <field name="user_id"/>
                                 <field name="loss_id" string="Efficiency"/>
                             </tree>
@@ -459,4 +459,4 @@
         <field name="view_id" ref="view_work_center_load_graph"/>
         <field name="act_window_id" ref="action_mrp_workcenter_load_report_graph"/>
     </record>
-</odoo>
+</odoo>