[FIX] web: handle focus for buttons cells in list

This is reproducible in lots of ways, here's one:
- Inventory -> Products -> Any storable product
- Click on Update Quantity
- Click on the cell where the 'History' and 'Set' button are

This raises a traceback as the `cell` assigned right before is null at
that point. Indeed, since those cells from a special kind of column made
of buttons (o_list_buttons), those don't have a `name` attribute to
find, hence the traceback.

closes odoo/odoo#128014

X-original-commit: 222dc64be51cc8e711278cff96392e755ba39fd4
Signed-off-by: Francois Georis (fge) <fge@odoo.com>

addons/web/static/src/views/list/list_renderer.js

@@ -1040,7 +1040,7 @@ export class ListRenderer extends Component {
                 const cell = this.tableRef.el.querySelector(
                     `.o_selected_row td[name='${column.name}']`
                 );
-                if (containsActiveElement(cell)) {
+                if (cell && containsActiveElement(cell)) {
                     this.lastEditedCell = { column, record };
                     // Cell is already focused.
                     return;

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

@@ -8239,6 +8239,31 @@ QUnit.module("Views", (hooks) => {
         );
     });
 
+    QUnit.test("click on a button cell in a list view", async (assert) => {
+        serverData.models.foo.records[0].foo = "bar";
+        await makeView({
+            type: "list",
+            resModel: "foo",
+            serverData,
+            arch: `
+                <tree editable="bottom" limit="1">
+                    <field name="foo"/>
+                    <button name="action_do_something" type="object" string="Action"/>
+                </tree>`,
+        });
+
+        // Need to set the line in edition. 
+        await click(target, "td[name=foo]");
+        assert.strictEqual(window.getSelection().toString(), "bar");
+
+        await click(target.querySelector(".o_data_cell.o_list_button"));
+        assert.strictEqual(
+            window.getSelection().toString(),
+            "bar",
+            "Focus should have returned to the editable cell without throwing an error"
+        );
+    });
+
     QUnit.test("click on a button in a list view", async function (assert) {
         assert.expect(10);