[IMP] mail: Pass the session uid on activity renderer

Purpose
=======

We could want to retrieve the session user id when rendering the next
activities on the chatter (For example in the new approvals module on the
enterprise repository).

At the same time, we used 'web.session' to retrieve this valued instead
of 'self.getSession().uid' which is deprecated.

addons/mail/static/src/js/activity.js

@@ -7,6 +7,7 @@ var AbstractField = require('web.AbstractField');
 var BasicModel = require('web.BasicModel');
 var core = require('web.core');
 var field_registry = require('web.field_registry');
+var session = require('web.session');
 var time = require('web.time');
 
 var QWeb = core.qweb;
@@ -486,6 +487,7 @@ var Activity = BasicActivity.extend({
         if (activities.length) {
             var nbActivities = _.countBy(activities, 'state');
             this.$el.html(QWeb.render('mail.activity_items', {
+                uid: session.uid,
                 activities: activities,
                 nbPlannedActivities: nbActivities.planned,
                 nbTodayActivities: nbActivities.today,
@@ -591,7 +593,7 @@ var KanbanActivity = BasicActivity.extend({
             self.$('.o_activity').html(QWeb.render('mail.KanbanActivityDropdown', {
                 selection: self.selection,
                 records: _.groupBy(setDelayLabel(activities), 'state'),
-                uid: self.getSession().uid,
+                uid: session.uid,
             }));
         });
     },