[IMP] website_event_exhibitor: improve sponsor type management

Choose lowest sponsor type as default when creating a new sponsor. Purpose
is to avoid being blocked by required fields. Choosing the lowest available
sponsor type allows to ease discovering the feature without breaking any
feature.

Also set a default sequence when creating a sponsor type to avoid jump
effect on list view: always send new sponsor types at the end.

Also set default ribbon as no ribbon to avoid a "void" entry in ribbon style
when creating new sponsor types.

Task ID-2558875
PR odoo/odoo#71787

addons/website_event_exhibitor/models/event_sponsor.py

@@ -25,8 +25,13 @@ class Sponsor(models.Model):
         'chat.room.mixin'
     ]
 
+    def _default_sponsor_type_id(self):
+        return self.env['event.sponsor.type'].search([], order="sequence desc", limit=1).id
+
     event_id = fields.Many2one('event.event', 'Event', required=True)
-    sponsor_type_id = fields.Many2one('event.sponsor.type', 'Sponsoring Level', required=True)
+    sponsor_type_id = fields.Many2one(
+        'event.sponsor.type', 'Sponsoring Level',
+        default=lambda self: self._default_sponsor_type_id(), required=True)
     url = fields.Char('Sponsor Website', compute='_compute_url', readonly=False, store=True)
     sequence = fields.Integer('Sequence')
     active = fields.Boolean(default=True)

addons/website_event_exhibitor/models/event_sponsor_type.py

@@ -9,10 +9,12 @@ class SponsorType(models.Model):
     _description = 'Event Sponsor Level'
     _order = "sequence"
 
+    def _default_sequence(self):
+        return (self.search([], order="sequence desc", limit=1).sequence or 0) + 1
+
     name = fields.Char('Sponsor Level', required=True, translate=True)
-    sequence = fields.Integer('Sequence')
-    display_ribbon_style = fields.Selection([
-        ('no_ribbon', 'No Ribbon'),
-        ('Gold', 'Gold'),
-        ('Silver', 'Silver'),
-        ('Bronze', 'Bronze')], string='Ribbon Style')
+    sequence = fields.Integer('Sequence', default=_default_sequence)
+    display_ribbon_style = fields.Selection(
+        [('no_ribbon', 'No Ribbon'), ('Gold', 'Gold'),
+         ('Silver', 'Silver'), ('Bronze', 'Bronze')],
+        string='Ribbon Style', default='no_ribbon')