[Grid] Excel export keeps loading when using OnPush change detection strategy

[zstoyanova9]

Description

When exporting the Grid to Excel and having a loading indicator configured to be displayed while the Grid is being exported and removed when the process is finished, the indicator does not disappear after the export has finished when the change detection strategy is OnPush.

Steps To Reproduce

1. Open the following StackBlitz example - https://stackblitz.com/edit/angular-uct6qswr-wfhxbpm3
2. Click the "Export to Excel" button.

Actual Behavior

The loading indicator does not disappear after the exporting has finished although the loading property of the Grid is correctly set to "false" upon the completion of the request.

Expected Behavior

The loading indicator should be removed after the exporting of the Grid has finished.

Workaround

As a temporary workaround, handle the excelExport event of the Grid - https://stackblitz.com/edit/angular-uct6qswr-2eyql1yq