[FIX] project: remove unnecessary condition in `_onDeleteColumn`

This commit removes the unnecessary condition on modelName as the code
stands in `ProjectTaskKanbanColumn` which is only used in the
`project.task` kanban view.

closes odoo/odoo#91891

Signed-off-by: William Braeckman (wbr) <wbr@odoo.com>

addons/project/static/src/js/project_kanban.js

@@ -63,7 +63,7 @@ const ProjectTaskKanbanColumn = KanbanColumn.extend({
      * @private
      */
     _onDeleteColumn: function (event) {
-        if (this.modelName === 'project.task' && this.groupedBy === 'stage_id') {
+        if (this.groupedBy === 'stage_id') {
             event.preventDefault();
             this.trigger_up('kanban_column_delete_wizard');
             return;