[WASM] Add CanvasSize to SkiaSharp.Views.Blazor Views

[JensKrumsieck]

Description of Change Fixes #1911 and #1888 : Added CanvasSize to Both (SKCanvasView.razor.cs and SKGLView.razor.cs) Views

public SKSize CanvasSize => canvasSize;

See also similar contribution: https://github.com/mono/SkiaSharp/pull/1832 & https://github.com/mono/SkiaSharp/issues/1831

Bugs Fixed

• Related to issue #1911

API Changes Added: File: SKCanvasView.razor.cs and SKGLView.razor.cs

public SKSize CanvasSize => canvasSize;

Behavioral Changes none

PR Checklist

• [ ] Has tests (if omitted, state reason in description)
• [ ] Rebased on top of main at time of PR
• [ ] Changes adhere to coding standard
• [ ] Updated documentation