[Meta] Improvements in Toast Deduplication

[delanni]

Scope leftover from: #161482 & #161738

This is the follow-up work on the topic of toast-storms/toast-floods. In the first iteration, we didn't take care of all aspects. Also, we require some work form EUI to have a nicer solution.

Requirements:

• Toasts who's message text is identical to a toast that is already on screen, will be combined into a single toast. (see Toast Deduplication & User Quality of Life Improvement #161482)
• Toasts that represent more than one instance of a message will show a counter badge that indicates how many times that message has recurred. (see Toast Deduplication & User Quality of Life Improvement #161482)
• A way of closing all toasts with a single click will be provided. (Clear All button and counter badge for the EuiGlobalToastList component eui#6945)
• When a toast storm (defined as a recurrence of any identical messages handled by the mechanism above) occurs the details including number of recurrences and the message text will be saved to the log file and generate a telemetry event.
• Telemetry event will be generated when the user clears the recurring toast, or when they navigate away from the page Send telemetry event when user clears deduped toast #166459
• Investigate a sort of notification-category-id to base toast grouping on. This would serve better than our current heuristic trying to merge based on titles/texts. See: [SharedUX] Merge similar toast messages in case of a toast-flood/storm #161738 (comment)

Historical discussions
Previous work
Related Jira Issue

[elasticmachine]

Pinging @elastic/appex-sharedux (Team:SharedUX)

[eokoneyo]

Improvements to toast deduplication done, toasts now have a clear all button, a telemetry event gets sent for every toast that either gets dismissed because it's display lifetime elapses, a user interacts with a single toast to dismiss it using it's close button, or either using the clear all button.