Update Blazor component to handle dotnet 9 rendermodes

[xela-trawets]

added checks to only create the Skia view when running in the browser

   private SKCanvasView? SKView { get; set; } = OperatingSystem.IsBrowser() ? new() : null;
   public override void Refresh()
   {
       SKView?.Invalidate();
   }

and

 @if (OperatingSystem.IsBrowser())
 {
     <SKCanvasView @ref="SKView"
                   style="width:inherit; height:inherit;"
                   OnPaintSurface="OnPaintSurface"
                   IgnorePixelScaling="true"
                   EnableRenderLoop="EnableRenderLoop"
                   @onpointerdown="OnPointerPressed"
                   @onpointermove="OnPointerMoved"
                   @onpointerup="OnPointerReleased"
                   @onwheel="OnPointerWheelChanged"
                   @onkeydown="OnKeyDown"
                   @onkeyup="OnKeyUp" />
 }

[xela-trawets]

Prerender is the default in mixed rendermode blazor

[xela-trawets]

The test fails due to "multiple SkiaSharp versions found"
This is intentional, I only touched the Blazor control.
I did try updating all the projects to SkiaSharp 3.116.1.
Didnt test that, it seems a big step.

Alex

[xela-trawets]

I would only take the blazor bits, the global skia version involved changes in heatmap.cs and SKGLElement.cs that were just me trying to pass the tests. (I will figure out the details later)..