Fix requests for object-type fields

[dyst5422]

Currently, the export to CSV functionality resuses the request from the page location. This adds all fields that are not script fields to the stored_fields on the request. This breaks the request for non-leaf fields (object-type fields) and causes the export to fail.

As per the note at the top of https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-stored-fields.html it seems like the stored_fields approach is not encouraged as is. Fields returned are already filtered with the _source.includes.

Perhaps this should still add fields in to the store_fields but check to make sure they are leaf fields first.

This fix stops adding to the stored_fields and thus fixes export for non-leaf fields.

Summary

Summarize your PR. If it involves visual changes include a screenshot or gif.

Checklist

Use strikethroughs to remove checklist items you don't feel are applicable to this PR.

• This was checked for cross-browser compatibility, including a check against IE11
• 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
• This was checked for keyboard-only and screenreader accessibility

For maintainers

• This was checked for breaking API changes and was labeled appropriately
• This includes a feature addition or change that requires a release note and was labeled appropriately

[elasticmachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[elasticmachine]

Pinging @elastic/kibana-app-arch

[lukasolson]

Related to #25068.

[lukasolson]

Firstly, sorry this has flown under the radar for so long.

Please take a look at my comment here.

While this fixes the scenario where you're attempting to query an object field that is not a leaf (but is stored in _source), it does not address the scenario where _source is disabled and you're trying to query a field that is stored. I've posted a suggested solution in the comment linked to above that may address this. If you'd like to update this PR with that suggestion, that'd be great! Otherwise I think we should probably close this PR in favor of opening a new one with the suggested solution.

Thanks for contributing!

[elasticmachine]

Pinging @elastic/kibana-stack-services

[bmcconaghy]

@tsullivan @joelgriffith can one of you take a look at this one?

[stacey-gammon]

Given no response, I'm going to close this. Thanks for your interest in contributing @dyst5422 and apologies it took us so long to respond. If you are interested in picking this back up, please take a look at @lukasolson's comment and re-open.