[FIX] web: kanban: missing quickcreate button in empty kanban

This commit fixes an issue where the quickcreate button was missing from
the kanban view when it was grouped by a non many2one field and contained
no record yet (so that no column is shown yet).

Steps to reproduce:

-Go to a kanban view on a model with no record
-Group by as scalar value (eg: Description)
->The "New" button disappears

OPW-3459808

closes odoo/odoo#143793

X-original-commit: 112ba1cb64b5170fdefd267de8e765f87b444b56
Signed-off-by: Lucas Perais (lpe) <lpe@odoo.com>
Signed-off-by: Julien Carion (juca) <juca@odoo.com>

addons/web/static/src/views/kanban/kanban_controller.js

@@ -249,7 +249,13 @@ export class KanbanController extends Component {
         if (!create) {
             return false;
         }
-        return list.isGrouped ? list.groups.length > 0 || !createGroup : true;
+        if (list.isGrouped) {
+            if (list.groupByField.type !== "many2one") {
+                return true;
+            }
+            return list.groups.length || !createGroup;
+        }
+        return true;
     }
 
     get canQuickCreate() {

addons/web/static/tests/views/kanban/kanban_view_tests.js

@@ -592,6 +592,35 @@ QUnit.module("Views", (hooks) => {
         assert.verifySteps(["rendered"]);
     });
 
+    QUnit.test("basic grouped rendering with no record", async (assert) => {
+        serverData.models.partner.records = [];
+
+        await makeView({
+            type: "kanban",
+            resModel: "partner",
+            serverData,
+            arch: `
+                <kanban class="o_kanban_test">
+                    <field name="bar" />
+                    <templates>
+                        <t t-name="kanban-box">
+                            <div>
+                                <field name="foo" />
+                            </div>
+                        </t>
+                    </templates>
+                </kanban>`,
+            groupBy: ["bar"],
+        });
+        assert.containsOnce(target, ".o_kanban_grouped");
+        assert.containsOnce(target, ".o_view_nocontent");
+        assert.containsOnce(
+            target,
+            ".o_control_panel_main_buttons .d-none.d-xl-inline-flex button.o-kanban-button-new",
+            "There should be a 'New' button even though there is no column when groupby is not a many2one"
+        );
+    });
+
     QUnit.test(
         "basic grouped rendering with active field (archivable by default)",
         async (assert) => {