Dispose Canvas then ensure surface handle release

Author: JimBobSquarePants

src/ImageSharp.Drawing.WebGPU/WebGPUSurfaceFrame{TPixel}.cs

@@ -56,10 +56,10 @@ public void Dispose()
         {
             this.Canvas.Flush();
             this.api.SurfacePresent((Surface*)this.surfaceReference.Handle);
+            this.Canvas.Dispose();
         }
         finally
         {
-            this.Canvas.Dispose();
             this.textureViewHandle.Dispose();
             this.textureHandle.Dispose();
             this.surfaceReference.Dispose();