Add sheet presentation detent & item parameter

[Louis-PAGNIER]

I added small support for .presentationDetents([]) with sheets.
Currently only support zero or one detent in the detents list.
This commit also add support for item binding in sheet and fullScreenCover.

It is one of my first pull requests, I'm new to SwiftUI and I don't know anything about Kotlin and Compose, so tell me if anything I made is bad or wrongly implemented.

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[Louis-PAGNIER]

Also, do you know how to implement the "tap outside the sheet to dismiss" behaviour like in SwiftUI ?

[marcprux]

This looks great! I'll experiment with it later today in the Showcase app's SheetPlayground and see if I can figure out the tap to dismiss, and likely merge it a bit later.

Thanks for the contribution!

[marcprux]

This looks good in my testing.

I looked into how to dismiss the ModalBottomSheet when tapping outside the sheet, and it sounds like the correct way to do this is to wrap the whole view in a ModalBottomSheetLayout.

Unfortunately, this would probably require some significant refactoring. @aabewhite might be able to provide more insight, but for the time being, you'll be limited to dismissing the sheet either by swiping it down, or adding some "Dismiss" button in the sheet itself.

[Louis-PAGNIER]

No problem, it's not currently very important.
Thank you for the merge & feedback :)

[marcprux]

Thank again for the PR. Please keep them coming!

I've released skip-ui 0.9.6 with the new .presentationDetents support and added a demo to the Showcase app's SheetPlayground.