[IMP] event_*: re-arrange stat buttons on the event form view

This commit improves the view inheritance priority and xpaths for
the inherited form views of event to arrange the stat buttons in
logical manner, regardless of installation order of the modules.
The stat button order should always be:

- Attendees
- Leads
- Sales
- Tracks
- Sponsors
- Rooms

Task-2585998
EnterprisePR-https://github.com/odoo/enterprise/pull/20082

closes odoo/odoo#74203

Related: odoo/enterprise#20082
Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>

addons/event_crm/views/event_event_views.xml

@@ -4,6 +4,7 @@
         <field name="name">event.event.form.inherit.event.crm</field>
         <field name="model">event.event</field>
         <field name="inherit_id" ref="event.view_event_form"/>
+        <field name="priority" eval="30"/>
         <field name="arch" type="xml">
             <xpath expr="//button[@name='%(event.act_event_registration_from_event)d']" position="after">
                 <button name="%(crm_lead_action_from_event)d" class="oe_stat_button" type="action" icon="fa-star"

addons/event_sale/views/event_views.xml

@@ -5,8 +5,9 @@
         <field name="name">event.form.inherit</field>
         <field name="model">event.event</field>
         <field name="inherit_id" ref="event.view_event_form"/>
+        <field name="priority" eval="20"/>
         <field name="arch" type="xml">
-            <xpath expr="//div[hasclass('oe_button_box')]" position="inside">
+            <xpath expr="//button[@name='%(event.act_event_registration_from_event)d']" position="after">
                 <field name="currency_id" invisible="1"/>
                 <button name="action_view_linked_orders"
                         type="object" class="oe_stat_button" icon="fa-dollar"

addons/website_event_meet/views/event_event_views.xml

@@ -5,6 +5,7 @@
         <field name="name">event.event.view.form.inherit.meet</field>
         <field name="model">event.event</field>
         <field name="inherit_id" ref="website_event.event_event_view_form"/>
+        <field name="priority" eval="10"/>
         <field name="arch" type="xml">
             <xpath expr="//field[@name='is_published']" position="before">
                 <button class="oe_stat_button" context="{'default_event_id': active_id, 'search_default_event_id': active_id}" icon="fa-comments-o" name="%(event_meeting_room_action)d" type="action">