Added SKCanvas.DrawPoints with Count Override

[DJGosnell]

Description of Change

Sometimes it's useful to pass an array of points to SKCanvas.DrawPoints but not to draw all of them. The API currently doesn't accept Spans<T> at this point, so it is a stop-gap until that decision has been made.

No tests added currently as there is not currently a test in the tests/Tests/SkiaSharp/SKCanvasTest.cs file for drawing points.

Bugs Fixed

• Fixes #2986

API Changes

Add public void SKCanvasDrawPoints (SKPointMode mode, SKPoint[] points, int count, SKPaint paint) overload.

Behavioral Changes

None.

Required skia PR

None.

PR Checklist

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