[Unified Search][Data Views] Allow to search by index pattern too

[jughosta]

Kibana version: main

Description of the problem including expected versus actual behavior:
Current DataViewPicker allows to filter data views by their name (custom name if provided or index pattern as a fallback). Users might want to be able to search by index pattern field of data views too even if that data view has a custom name.

Steps to reproduce:

1. Create a data view with a custom name which is different from its index pattern
2. Try to find that data view by entering index pattern in the search field of DataViewsList

[jughosta]

Linking to #59432

[jughosta]

cc @stratoula

[elasticmachine]

Pinging @elastic/kibana-data-discovery (Team:DataDiscovery)

[kertal]

One more thing we might consider: Allowing also to search by id. While for the generated one this makes no sense, but we also allow to provide custom ids

[elasticmachine]

Pinging @elastic/kibana-app-services (Team:AppServicesUx)

[kertal]

Another reason why we need to do this. When we allow ad-hoc data views, once the user enters a text into the search box, we need to be sure that all possible matches of data view for the given pattern are displayed.

in the current state, when the user would enter indexName and indexName would have a custom name Index Name, nothing would be found and given we search the name of indices that would match, we would suggest to use the entered name for an ad-hoc data view.

[stratoula]

This is easily done with EuiSelectable, we just need to pass a secondary field to search.

Check https://elastic.github.io/eui/#/forms/selectable --> Custom content