espcoder

### Steps to reproduce Link to live example: (required): https://codesandbox.io/p/sandbox/mui-datagrid-collapsible-group-header-disappears-fhz639 * the sandbox starts with the collapsible column header example on the [docs page](https://mui.com/x/react-data-grid/column-groups/#collapsible-column-groups) and adds a column header group...