🚀 - [Skeleton] Accessibilty enhancements (aria) for notifying screen-readers

[ajitzero]

Description

Enhancement for: https://taiga-ui.dev/directives/skeleton

Brief:
We should consider using one or more of the following aria attributes to inform assistive technologies regarding the current state of skeleton loaders:

• aria-busy: Most relevant.
• aria-hidden: Technically correct, but is likely not applicable. (Mentioning it here for posterity. I'm not an expert.)
• aria-live: Disrupts the user's focus on status change, either immediately (default) or when the user is idle (polite). This is good, unless there are multiple notifications for a group of skeleton loaders.

Problems:

• aria-live is important, but difficult to assign to a group of skeleton elements. We may need to introduce a [tui-skeleton-group] directive for the parent, which solves this issue but is also easy for developers to forget to use, even if it exists.
• Is it possible to apply it only to the parent element and not recursively to the children? I may be misunderstanding how the component works, so this may be a non-issue. aria-atomic may help solve the issue if this is a problem.