[Data Views] Support of AbortSignal for getFieldsForWildcard

[alexwizp]

Some plugins like TSVB use getFieldsForWildcard method to get fields for es indexes.
I see that inside this method there are calls to es cluster like:

  return await callCluster.fieldCaps({
       index: indices,
       fields: '*'
       ignore_unavailable: true
       index_filter: filter,
       ...fieldCapsOptions,
     });

Since the query behind these fields can take quite a long time when using wildcards indexes, I think we should be able to cancel it

Can we add support for passing AbortSignal?

[elasticmachine]

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

[mattkime]

Since the query behind these fields can take quite a long time when using wildcards indexes

This should rarely be the case as data view loading is dependent upon it. That said, I think it makes sense to be able to cancel queries. Implementation looks straight forward but it would be good to have an initial consumer to verify this works as intended. Could you implement it with guidance and / or review from @elastic/kibana-app-services ?

[elasticmachine]

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

[kertal]

Closing this because it's not planned to be resolved in the foreseeable future. It will be tracked in our Icebox and will be re-opened if our priorities change. Feel free to re-open if you think it should be melted sooner.