[FIX] stock: forecast button color

Steps to reproduce:
- Enable multistep routes (3 steps delivery)
- Create a new storable product (0 on hand quantity)
- Confirm an SO with that product

Bug:
forecast button is correctly red on the SO line but it's green on the
stock pickings

Fix:
button should be green if it's possible to reserve quantity red otherwise

opw-3440627

closes odoo/odoo#134335

Signed-off-by: Quentin Wolfs (quwo) <quwo@odoo.com>

addons/stock/views/stock_picking_views.xml

@@ -386,9 +386,9 @@
                                     <field name="product_packaging_id" groups="product.group_stock_packaging"/>
                                     <field name="product_uom_qty" string="Demand" attrs="{'column_invisible': [('parent.immediate_transfer', '=', True)], 'readonly': ['|', ('is_initial_demand_editable', '=', False), '&amp;', '&amp;', ('show_operations', '=', True), ('is_locked', '=', True), ('is_initial_demand_editable', '=', False)]}"/>
                                     <button type="object" name="action_product_forecast_report" icon="fa-area-chart" 
-                                        attrs="{'invisible': ['|', ('forecast_availability', '&lt;', 0), '|', ('parent.immediate_transfer', '=', True), '&amp;', ('parent.picking_type_code', '=', 'outgoing'), ('state', '!=', 'draft')]}"/>
+                                        attrs="{'invisible': ['|', ('forecast_availability', '&lt;=', 0), '|', ('parent.immediate_transfer', '=', True), '&amp;', ('parent.picking_type_code', '=', 'outgoing'), ('state', '!=', 'draft')]}"/>
                                     <button type="object" name="action_product_forecast_report" icon="fa-area-chart text-danger" 
-                                        attrs="{'invisible': ['|', ('forecast_availability', '&gt;=', 0), '|', ('parent.immediate_transfer', '=', True), '&amp;', ('parent.picking_type_code', '=', 'outgoing'), ('state', '!=', 'draft')]}"/>
+                                        attrs="{'invisible': ['|', ('forecast_availability', '&gt;', 0), '|', ('parent.immediate_transfer', '=', True), '&amp;', ('parent.picking_type_code', '=', 'outgoing'), ('state', '!=', 'draft')]}"/>
                                     <field name="forecast_expected_date" invisible="1"/>
                                     <field name="forecast_availability" string="Reserved"
                                         attrs="{'column_invisible': ['|', '|', ('parent.state', 'in', ['draft', 'done']), ('parent.picking_type_code', '!=', 'outgoing'), ('parent.immediate_transfer', '=', True)]}" widget="forecast_widget"/>