Update Uno version, Uno TFMs to .NET 8

[Arlodotexe]

This PR:

• Updates our Uno packages to the latest stable version
• Closes Update Uno Platform library TFMs to net8.0 #182. Updates the TFMs that Uno runs on from net7.0 to net8.0
• Fixes any issues that arise from the move to net8.0

[Arlodotexe]

Opened as a draft. We're seeing linker issues when compiling release mode. Tested against the main repo by running this command:

.\tooling\Build-Toolkit-Gallery.ps1 -Head wasm -MultiTargets wasm -Components All -WinUIMajorVersion 2 -Release

We see this error message with no additional details:

C:\Users\arlog\.nuget\packages\uno.wasm.bootstrap\7.0.29\build\Uno.Wasm.Bootstrap.targets(206,3): error : System.Exception: Failed to exe 
       cute the linker [C:\Users\arlog\source\repos\Windows\tooling\ProjectHeads\AllComponents\wasm\CommunityToolkit.App.Wasm.csproj]

This error is also showing in the CI.

[Arlodotexe]

Thanks @jeromelaban for the help!

For reference, the issue was that the Uno.Wasm.Bootstrap package version doesn't align with Uno.UI/Uno.WinUI/etc. via our CommonUnoPackageVersion property and had to be updated separately. We'll need to keep this in mind for future updates. Unfortunately, we can't make use of the Uno SDK to keep things in step because it doesn't support UWP.

We should be able to close this off and include the changes in the 8.1 update.

[michael-hawker]

May want to look at the 422 equivalent as there's an Android error there:

error NETSDK1181: Error getting pack version: Pack 'Microsoft.Android.Ref.33' was not present in workload manifests. [C:\a\Windows\Windows\components\Triggers\samples\Triggers.Samples.csproj::TargetFramework=net8.0-android33.0]

Build error in linked 422

[jeromelaban]

May want to look at the 422 equivalent as there's an Android error there:

This generally happens when the TargetPlatformVersion is 33 instead of 34 (which net8 targets).

[Arlodotexe]

Thanks Jerome, I'll give that a try. Found additional information on this error message here.