Consider to deprecate toExists assertion

[gosha212]

Describe your idea

Because of different implementations of recycling long lists in Android and in iOS it is hard to make toExists api to work constantly on both platforms.
Here is an example:
Create list with 30 items.
On iOS toExists api will return true on item 29 although it is not visible.
On Android the same function will return false because this item is not visible and Android is not rendering it.