[REM] calendar: Remove useless is_attendee field

The field is never used and invisible in the view.

Task 2126717
PR #42031
PR Enterprise odoo/enterprise#8006

addons/calendar/models/calendar_event.py

@@ -188,7 +188,6 @@ class Meeting(models.Model):
 
     name = fields.Char('Meeting Subject', required=True)
 
-    is_attendee = fields.Boolean('Attendee', compute='_compute_attendee')
     attendee_status = fields.Selection(Attendee.STATE_SELECTION, string='Attendee Status', compute='_compute_attendee')
     display_time = fields.Char('Event Time', compute='_compute_display_time')
     start = fields.Datetime('Start', required=True, tracking=True, default=fields.Date.today, help="Start date of an event, without time for full days events")
@@ -206,6 +205,7 @@ class Meeting(models.Model):
     show_as = fields.Selection([('free', 'Free'), ('busy', 'Busy')], 'Show Time as', default='busy', required=True)
 
     # linked document
+    # LUL TODO use fields.Reference ?
     res_id = fields.Integer('Document ID')
     res_model_id = fields.Many2one('ir.model', 'Document Model', ondelete='cascade')
     res_model = fields.Char('Document Model Name', related='res_model_id.model', readonly=True, store=True)
@@ -272,7 +272,6 @@ class Meeting(models.Model):
     def _compute_attendee(self):
         for meeting in self:
             attendee = meeting._find_my_attendee()
-            meeting.is_attendee = bool(attendee)
             meeting.attendee_status = attendee.state if attendee else 'needsAction'
 
     def _compute_display_time(self):

addons/calendar/views/calendar_views.xml

@@ -95,7 +95,6 @@
                     <widget name="web_ribbon" title="Archived" bg_color="bg-danger" attrs="{'invisible': [('active', '=', True)]}"/>
                     <field name="res_model" invisible="1" />
                     <field name="res_id" invisible="1" />
-                    <field name="is_attendee" invisible="1"/>
                     <field name="attendee_status" invisible="1"/>
                     <field name="active" invisible="1"/>
                     <div class="oe_title">