Upgrade WASDK from 1.6 to 1.8

[Avid29]

PR Type

What kind of change does this PR introduce?

• Build or CI related changes

Please check if your PR fulfills the following requirements:

• [x] Created a feature/dev branch in your fork (vs. submitting directly from a commit on main)
• [x] Based off latest main branch of toolkit
• [ ] Tested code with current supported SDKs (https://github.com/CommunityToolkit/WindowsCommunityToolkit-design-assets)
• [ ] Tests for the changes have been added (if applicable)
• [x] Header has been added to all new source files
• [ ] Contains NO breaking changes

Other information

This is currently blocked by 2 dependencies, which must be updated to 1.8 before we can update

Blocked by

• [x] Microsoft.Xaml.Behaviors.WinUI.Managed (Currently on version 3.0.0 - using wasdk 1.6.250108002)
• [ ] Microsoft.Graphics.Win2D (Currently on version 1.3.2 - using wask 1.6.241114003)

[Avid29]

One dependency has been updated! https://github.com/microsoft/XamlBehaviors/pull/314