Refactor: A single `Snackbar` with one `autoHideDuration={6000}` now wraps a list of toasts. The timer is shared across the whole list, which has two awkward consequences when warnings are pushed at different moments:

[AlexeyGirin]

A single Snackbar with one autoHideDuration={6000} now wraps a list of toasts. The timer is shared across the whole list, which has two awkward consequences when warnings are pushed at different moments:

• A toast added shortly before the timer expires gets cut short.
• When the timer fires, onClose calls handleCloseErrorTooltip() with no argument, which clears all tooltips at once — so a freshly added toast can disappear immediately.

For independent per-toast lifetimes, render each toast in its own Snackbar (or manage per-message timeouts in the slice and dispatch closeErrorTooltip(text) per item).

Originally posted by @claude[bot] in #10140 (comment)