[ADD] mail: quick-open related record from activity

Current behavior before PR: You have to find the right menu/view and then take
over the ID stored on the activity (through export) to find back the record.
This is annoying, painful and error prone.

Desired behavior after PR is merged: By adding a smartbutton the user can
quick-navigate to the related record in a second. This allows for quickly
finding and opening records which is usually handy when debugging things or
finding back related records.

Task-2868230

closes odoo/odoo#91230

Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>

addons/mail/models/mail_activity.py

@@ -568,6 +568,17 @@ class MailActivity(models.Model):
     def action_close_dialog(self):
         return {'type': 'ir.actions.act_window_close'}
 
+    def action_open_document(self):
+        """ Opens the related record based on the model and ID """
+        self.ensure_one()
+        return {
+            'res_id': self.res_id,
+            'res_model': self.res_model,
+            'target': 'current',
+            'type': 'ir.actions.act_window',
+            'view_mode': 'form',
+        }
+
     def activity_format(self):
         activities = self.read()
         mail_template_ids = set([template_id for activity in activities for template_id in activity["mail_template_ids"]])

addons/mail/views/mail_activity_views.xml

@@ -99,6 +99,11 @@
         <field name="arch" type="xml">
             <form string="Log an Activity" create="false">
                 <sheet string="Activity">
+                    <div class="oe_button_box" name="button_box">
+                        <button name="action_open_document" string="Open Document"
+                                type="object" class="oe_link" icon="fa-file-text-o"
+                                attrs="{'invisible': ['|', ('res_model', '=', False), ('res_id', '=', 0)]}"/>
+                    </div>
                     <group invisible="1">
                         <field name="activity_category" invisible="1" />
                         <field name="res_model" invisible="1"/>