[Uptime] Fix PingList pagination - #61481

Summary

Fixes #61315.

The PingList component in Uptime has a broken pagination experience, which can lead to users being misled that they only have n items when really they have m items where n is the number of rows on the page and m is the total document count for the given monitor ID.

This request aims to fix that by updating the UI, API, and ES query responsible for fetching and rendering this information.

Testing this PR

1. Go to detail page for a monitor that has at least ~1000 documents.
2. Change the page size to the various values supplied, and make sure the numbers you see are accurate.
3. Change the page selections and make sure they continue to be sorted by timestamp appropriately.

Checklist

Delete any items that are not applicable to this PR.

• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Unit or functional tests were updated or added to match the most common scenarios
• This was checked for keyboard-only and screenreader accessibility
• This renders correctly on smaller devices using a responsive layout. (You can test this in your browser
• This was checked for cross-browser compatibility, including a check against IE11

For maintainers

• This was checked for breaking API changes and was labeled appropriately