Apply WinUI 3 exception handler in Sentry core

[mattjohnsonpint]

Previously we were hooking up the WinUI 3 unhandled exception handler in Sentry.Maui only.

This moves that to an internal integration in Sentry core, so that it can also be used by WinUI 3 apps directly, or by other non-MAUI platforms that can leverage WinUI 3, such as Uno Platform.

Note that this doesn't apply for UWP (WinUI 2) apps. Those will still need to hook up the handler directly, per our configuration guide

I also added a button to the MAUI sample that causes a crash on a background thread, which I used to verify that both types of crashes work. One is caught by this integration, the other is caught by the existing AppDomain integration.

[SimonCropp]

forgive my ignorance, i can bever remember all the windows UI approaches. but isnt uap the tfm for winui? and wouldnt that make this easier?

[mattjohnsonpint]

forgive my ignorance, i can bever remember all the windows UI approaches. but isnt uap the tfm for winui? and wouldnt that make this easier?

That's for UWP (WinUI 2). This is for WinUI 3.

Also, having a Windows target would mean a lot of build and CI changes, for repackaging, etc. Better to avoid it if possible.

[SimonCropp]

Also, having a Windows target would mean a lot of build and CI changes, for repackaging, etc. Better to avoid it if possible.

ok. i was assuming u had already considered it. thanks

[SimonCropp]

few minor suggestions above. but nothing that "needs" to be done.