[TriangleAnnotator, DotAnnotator] - allow customization of the contour color #1403

[Kadermiyanyedi]

This PR introduces a new outline_color argument to the TriangleAnnotator and DotAnnotator classes, allowing users to customize the outline color when rendering annotations. Previously, while users could set outline_thickness to render an outline, the color was not configurable. With this enhancement, outline_color can now be set and will integrate seamlessly with the existing color_lookup system, accepting values of type Union[Color, ColorPalette].

Key Changes

• Added outline_color argument to TriangleAnnotator and DotAnnotator.
• Integrated outline_color with the existing color_lookup mechanism.

resolve #1403

For testing purposes, please refer to the provided Colab link.

Please review thank you :)

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

---

Kader Miyanyedi seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}