[Meta] CommunityToolkit should have at least some downlevel WinAppSDK support

[citelao]

Describe the bug

I believe the CommunityToolkit has a policy of updating to the latest build of WinAppSDK as it gets updated.

Unfortunately, this makes consuming components hard in production software, which cannot always upgrade to the latest versions of WinAppSDK instantly. Especially for components that don't depend on the latest version, can CommunityToolkit relax these requirements?

Steps to reproduce

Example error when trying to use the new `DependencyPropertyGenerator`:


NU1605: Warning As Error: Detected package downgrade: Microsoft.WindowsAppSDK from 1.6.250108002 to 1.6.240923002. Reference the package directly from the project to select a different version. 
MyApp -> CommunityToolkit.Labs.WinUI.DependencyPropertyGenerator 0.1.250206-build.2040 -> Microsoft.WindowsAppSDK (>= 1.6.250108002) 
MyApp-> Microsoft.WindowsAppSDK (>= 1.6.240923002)

Expected behavior

Especially for DependencyPropertys, which don't change much, we should relax the version requirements.

Code Platform

• UWP
• WinAppSDK / WinUI 3
• Web Assembly (WASM)
• Android
• iOS
• MacOS
• Linux / GTK

Windows Build Number

• Windows 10 1809 (Build 17763)
• Windows 10 1903 (Build 18362)
• Windows 10 1909 (Build 18363)
• Windows 10 2004 (Build 19041)
• Windows 10 20H2 (Build 19042)
• Windows 10 21H1 (Build 19043)
• Windows 11 21H2 (Build 22000)
• Other (specify)

App minimum and target SDK version

• Windows 10, version 1809 (Build 17763)
• Windows 10, version 1903 (Build 18362)
• Windows 10, version 1909 (Build 18363)
• Windows 10, version 2004 (Build 19041)
• Other (specify)

Help us help you

Yes, I'd like to be assigned to work on this item.

[michael-hawker]

@citelao it's not a policy we have, but we have needed to take the latest version updates for enabling Native AOT compatibility (or other bug fixes in the past).

In this particular case for the DP generator, the inter-version between 1.6 builds may not be significant here, but everything is tied to a shared infrastructure here.

I agree, that this reduces the ability for some folks to consume packages, but with the underlying updates to the platform, it's been a forcing function for us of late.