Updates for net9.0

[pjcollins]

Context: dotnet/android@dbdc5fa
Context: dotnet/macios@4489999

Updates samples and template to target net9.0, using the new
@(AndroidGradleProject) and @(XcodeProject) build
actions added to the .NET MAUI SDKs.

The CommunityToolkit.Maui.NativeLibraryInterop.BuildTasks project
has been removed as it is no longer relevant for net9.0.

[pjcollins]

Aside from some CI changes here this is pretty much ready to go when GA is out, going to add some folks for review

[Peru-S]

Curious: does this PR require objective sharpie still? Or is that transmogrified part of dotnet9?

[pjcollins]

Curious: does this PR require objective sharpie still? Or is that transmogrified part of dotnet9?

As part of the changes for .NET 9, objective sharpie has become a manual step that you can integrate into your build process as needed. More information about this change can be found in the corresponding docs PR here https://github.com/MicrosoftDocs/CommunityToolkit/pull/487/files

[Peru-S]

This PR is useful - but I will use the issue thread to get the correct sharpie bind magic command instead to not conflate this PR thread any more.
Thank you @pjcollins .

[rachelkang]

LGTM!!!

question: sharpie generates the macios API as "GetStringWithString" - previously, it would just generate it as "GetString" though (so there was no need to manually change what was generated to match). just curious if you have any idea why we didn't have to before?

[pjcollins]

LGTM!!!

question: sharpie generates the macios API as "GetStringWithString" - previously, it would just generate it as "GetString" though (so there was no need to manually change what was generated to match). just curious if you have any idea why we didn't have to before?

I don't think anything here with respect to sharpie output should have changed, but we have manually touched up most of the ApiDefinition files that are included in this repo

[mikeparker104]

Looks good 👍