DragGestureRecognizer should allow to point to another view as placeholder view

Description

When i use DragGestureRecognizer on Xamarin.Forms, it will automatically get the view that i bound the DragGestureRecognizer on as a placeholder view when user long click on it and start moving their finger.

The problem is not every scenario we always want the user interact with the entire view. Sometimes, they can only drag and drop on an icon (for avoiding conflicting gestures on the entire view).

But if we implement the DragGestureRecognizer on that Icon/Image only, we can only see the placeholder as the Icon/Imagge

Therefore, I think it's great to have a feature that telling Xamarin before creating the placeholder pointing to another view instead of the view it's bounding to.

Public API Changes

On DragStartingEventArgs from DragStarting of the GestureRecognizer, we should have a property like

    public class DragStartingEventArgs : EventArgs
    {
        public DragStartingEventArgs()
        {
            Data = new DataPackage();
        }

        public bool Handled { get; set; }
        public bool Cancel { get; set; }
        public DataPackage Data { get; private set; }
                public VisualElement PlaceholderView { get; set; } // we can set this property when DragStarting invoked
    }

Intended Use-Case

Use case mentioned in Description

dotnet / maui