[FIX] stock: make replenishment buttons visible with groupby

Steps to reproduce:

- Install stock
- Go to operations/replenishment
- Group by product or whatever
- Select one or all items

The buttons order and snooze disappear when using group by, to solve the problem we take advantage of showButtons property.

opw-3129241
opw-3126708
opw-3114485

closes odoo/odoo#110475

X-original-commit: 3527215730b0454cf92bf35a16f541748ad294ba
Signed-off-by: William Henrotin (whe) <whe@odoo.com>
Signed-off-by: nea@odoo.com <nea@odoo.com>

addons/stock/static/src/views/stock_orderpoint_list_buttons.xml

@@ -5,7 +5,7 @@
         <xpath expr="//button[hasclass('o_list_button_add')]" position="attributes">
             <attribute name="class">btn btn-secondary o_list_button_add</attribute>
         </xpath>
-        <xpath expr="//button[hasclass('o_list_button_add')]" position="before">
+        <xpath expr="//t[@t-if='props.showButtons']" position="before">
             <button t-if="nbSelected" type="button" t-on-click="onClickOrder"
                     class="o_button_order btn btn-primary me-1">
                 Order