Closes: #81476

Summary

For dashboard's filter bar to work visualisations communicate its index-patterns.
Some visualisations don't do that (#19408)
But according to (#19408 (comment)) TSVB should.

This is causing bugs and confusions with how filter bar is working on a dashboard when TSVB is used.
Especially filter bar is almost non usable for dashboards that have only TSVB visualisations and use non-default index patterns.

Steps to reproduce:

1. Create a TSVB with non default index pattern
2. Create a dashboard with single TSVB lib
3. Try to use a filter bar and notice that there is no way to use pick a filter for used index pattern

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
• Documentation was added for features that require explanation or tutorials
• Unit or functional tests were updated or added to match the most common scenarios
• Any UI touched in this PR is usable by keyboard only (learn more about keyboard accessibility)
• Any UI touched in this PR does not create any new axe failures (run axe in browser: FF, Chrome)
• This renders correctly on smaller devices using a responsive layout. (You can test this in your browser)
• This was checked for cross-browser compatibility

For maintainers

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