[FIX] web: delete a record in a grouped kanban

Before this commit, in a grouped kanban view, when the "delete" button
of a card is clicked, the card is deleted but a "Load more..." is
displayed in the column.

Why is this?
The group counter is not correctly decremented when the record is deleted

How to reproduce :
- Go to a grouped kanban view with a delete button on its cards
- Click on the delete button

Before this commit:
The record is deleted and "Load more..." is displayed in the record column.

After this commit:
The record is deleted.

closes odoo/odoo#101817

X-original-commit: c97551a5aac6eaa0ca3d750039a65e3e03a453da
Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>

addons/web/static/src/views/relational_model.js

@@ -2579,8 +2579,9 @@ export class Group extends DataPoint {
     /**
      * @see DynamicRecordList.deleteRecords
      */
-    async deleteRecords() {
-        return this.list.deleteRecords(...arguments);
+    async deleteRecords(records) {
+        this.count = this.count - records.length;
+        return this.list.deleteRecords(records);
     }
 
     empty() {

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

@@ -1182,6 +1182,36 @@ QUnit.module("Views", (hooks) => {
         }
     );
 
+    QUnit.test("click on a button type='delete' to delete a record in a column", async (assert) => {
+        await makeView({
+            type: "kanban",
+            resModel: "partner",
+            serverData,
+            arch: `<kanban limit="3">
+                    <templates>
+                        <t t-name="kanban-box">
+                            <div>
+                                <div><a role="menuitem" type="delete" class="dropdown-item o_delete">Delete</a></div>
+                                <field name="foo"/>
+                            </div>
+                        </t>
+                    </templates>
+                </kanban>`,
+            groupBy: ["product_id"],
+        });
+        let column = getColumn();
+        assert.containsN(column, ".o_kanban_record", 2);
+        assert.containsNone(column, ".o_kanban_load_more");
+
+        await click(column.querySelector(".o_kanban_record .o_delete"));
+        assert.containsOnce(target, ".modal");
+
+        await click(target, ".modal .btn-primary");
+        column = getColumn();
+        assert.containsOnce(column, ".o_kanban_record");
+        assert.containsNone(column, ".o_kanban_load_more");
+    });
+
     QUnit.test("kanban with an action id as on_create attrs", async (assert) => {
         const actionService = {
             start() {