Align the default user-id between the C# and native layers

[bruno-garcia]

SDKs usually have some default 'installation-id' as a User. When capturing from C# and Native those don't match.

Relates to: getsentry/sentry-cocoa#1554

[bruno-garcia]

API on cocoa added: getsentry/sentry-cocoa#1680

[bruno-garcia]

@marandaneto is there a way to get the default/built-in installation-id from Android?
Do we align those already between Java/NDK layers?

Now I wonder if we're using this as the Id on cocoa or it's a different one. Installation-Id we use for did in Sessions, right? @philipphofmann might know

[marandaneto]

NDK events don't set the user id, so the Android layer does it, you can get it via Installation.id(context), but it's package-private, if you need to access it, we need to make it public.
iOS just changed that and it has to be fixed on Flutter and React Native getsentry/sentry-cocoa#1680