[IMP] stock: add is_signed boolean computed field

signaature field was used in listview and it was displaying size of the
signature file, it has been done in commit: 4bdbb9b
but as discussed on PR: odoo#72276
we added is_signed computed boolean field to display it like boolean as boolean
widget is supported only on boolean type field.

task-2580117

addons/stock/models/stock_picking.py

@@ -369,6 +369,7 @@ class Picking(models.Model):
         help="When validating the transfer, the products will be assigned to this owner.")
     printed = fields.Boolean('Printed', copy=False)
     signature = fields.Image('Signature', help='Signature', copy=False, attachment=True)
+    is_signed = fields.Boolean('Is Signed', compute="_compute_is_signed")
     is_locked = fields.Boolean(default=True, help='When the picking is not done this allows changing the '
                                'initial demand. When the picking is done this allows '
                                'changing the done quantities.')
@@ -411,6 +412,11 @@ def _compute_delay_alert_date(self):
         for picking in self:
             picking.delay_alert_date = delay_alert_date_data.get(picking.id, False)
 
+    @api.depends('signature')
+    def _compute_is_signed(self):
+        for picking in self:
+            picking.is_signed = picking.signature
+
     @api.depends('move_lines', 'state', 'picking_type_code', 'move_lines.forecast_availability', 'move_lines.forecast_expected_date')
     def _compute_products_availability(self):
         self.products_availability = False

addons/stock/views/stock_picking_views.xml

@@ -189,7 +189,7 @@
                     <field name="location_id" options="{'no_create': True}" string="From" groups="stock.group_stock_multi_locations" optional="show"/>
                     <field name="location_dest_id" options="{'no_create': True}" string="To" groups="stock.group_stock_multi_locations" optional="show"/>
                     <field name="partner_id" optional="show"/>
-                    <field name="signature" string="Signed" optional="hide" groups="stock.group_stock_sign_delivery"/>
+                    <field name="is_signed" string="Signed" optional="hide" groups="stock.group_stock_sign_delivery"/>
                     <field name="user_id" optional="hide" widget="many2one_avatar_user"/>
                     <field name="scheduled_date" optional="show" widget="remaining_days" attrs="{'invisible':[('state', 'in', ('done', 'cancel'))]}"/>
                     <field name="date_deadline" optional="hide" widget="remaining_days" attrs="{'invisible':[('state', 'in', ('done', 'cancel'))]}"/>