closes #1077, #1153, #1167

This PR adds support for sibling portals by correctly implementing outside interactions using a stack. Previously outside interactions did not work correctly when using sibling portals.

Also, please don't be intimidated by the "size" of this PR. It's mostly tests and other than that, this PR is 70 additions and 161 deletions.

Throughout this PR, I will mention the term "floating element", what I mean by that is anything that can be mounted into a portal (i.e. dialog, tooltip, popover, link preview, menu, tooltip, listbox etc.).

The correct way to implement outside interactions is by only closing the top-most floating element given the top-most element has closeOnOutsideClick: true. If the top-most element has closeOnOutsideClick: false, no elements should close since the top-most element "asked" to not close on an outside interaction.

I also fixed an issue with the Tags Input when it's nested inside another floating element like a Popover. When editing a tag, if you click outside, we should just cancel editing. However, the popover would also close. This is solved by using the new useInteractOutside() on the edit builder to prevent other floating elements from reacting to outside interactions.

Here is a video showing nested floating elements and outside interactions only closing the top-most floating element. (ignore the craziness of the nested elements :))

Also, to prevent issue #1167, where interact outside doesn't fire when clicking outside opens a new floating element, which is caused by checking too late whether the element is at the top of the stack. This is because the outside interaction triggers the opening of another floating element, so by the time pointerup fires for the first floating element, the second floating element had already been added to the stack. This is prevented in this PR by checking in pointerup whether the element was at the top of the stack during pointerdown. I added a regression test for this as well.

Before

After