[Time To Visualize] Extract Index Patterns from By Value Panels

[ThomThomson]

Problem

currently, index pattern references from 'by value' panels on a dashboard are not extracted properly into the dashboard itself. Drilldown dashboard references are extracted this way, so likely something similar needs to be done.

Relationship explorer for a dashboard with a by value panel that has a drilldown:

The index pattern from that panel should also be propagated.

[elasticmachine]

Pinging @elastic/kibana-presentation (Team:Presentation)

[kmartastic]

@crob611 @ThomThomson -- I'm sorry, I don't understand the issue reading the problem statement above. Can you clarify for me?

[crob611]

@kmartastic This was fixed by #91567 but I'll summarize it for you. Before TimeToVisualize, a dashboard panels were all backed by saved objects. This made it easy when saving a dashboard to know the other saved objects that it referenced.

With TimeToVisualize, now the panels are not backed by a saved object, but they could still be referencing saved objects, such as an index pattern. The point of this issue was to make sure that dashboard was appropriately extracting these references that are not as obvious as the panel by reference scenario.