Exception when adding items from another thread

[daniol]

Describe the bug
MAUI.DataGrid does not internally handle thread synchronization for updates to its data source. When an item is added to the ObservableCollection from a thread different than the UI thread, the DataGrid does not automatically marshal the change back to the UI thread.
Calling MainThread.BeginInvokeOnMainThread when adding a item to the ItemSource collection solves the problem.

To Reproduce
Steps to reproduce the behavior:

1. Define a DataGrid with a ItemsSource associated to an ObservableCollection
2. Add an Item to the ObservableCollection from another thread, for example with Task.Run(() => itemList.Add(x));
3. A COM exception is thrown when _paginationStepper.IsEnabled is changed

   Maui.DataGrid/Maui.DataGrid/DataGrid.xaml.cs

   Line 1231 in 9b24fb1

   _paginationStepper.IsEnabled = value > 1;

Expected behavior
Either no exception, or explicitly state on the documentation that calling BeginInvokeOnMainThread is necessary.