[FIX] crm: Leads analysis graph view

In saas-6, the pivot and the graph view have been
split in two separated type of views.

Otherwise said, there is no longer any graph view
with as type "pivot".

opw-658725

addons/crm/report/crm_lead_report_view.xml

@@ -19,7 +19,7 @@
             <field name="name">crm.lead.report.graph.two</field>
             <field name="model">crm.lead.report</field>
             <field name="arch" type="xml">
-                <graph string="Leads Analysis" type="pivot" stacked="True">
+                <graph string="Leads Analysis" stacked="True">
                     <field name="create_date" type="row"/>
                     <field name="user_id" type="col"/>
                 </graph>