Improve kql error message handling and avoid fetcihng twice

[flash1293]

Fixes #48392

The code building the errors message for a KQL parsing exception assumes the expected property is an array - in some cases (e.g. when using a leading wildcard) this is not the case.

This PR makes sure in these cases a meaningful error message is built.

While working on this problem I noticed that Discover sends two requests when updating the query because there is a watcher on the query state that triggers an additional fetch. In this PR it is made sure that the fetch is only triggered when necessary.

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 6710c08

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@elasticmachine merge upstream

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[lizozom]

LGTM

[Bargs]

Error message fix looks good 👍

The change to the watcher does fix the double request, though I'm a bit worried we're missing whatever change caused this to happen in the first place. That watcher has been around for a long time but the double request seems to be a recent problem. Also Visualize and Dashboard have similar watchers, but don't have this problem. They've diverged enough that I can't immediately see what the difference is though. I thought courier had some deduplication logic in the past, I wonder if anything changed there @lukasolson ?

In any case I suppose this fix works fine for the problem at hand in Discover, I'm just nervous that we don't know why it broke.

[flash1293]

@Bargs I can reproduce the problem on upstream/7.5 and on a 7.5.0 cloud instance - seems like it has been a problem for a while. The implementation in visualize has the check whether the migrated query has changed (which would prevent the double fetch: https://github.com/elastic/kibana/blob/master/src/legacy/core_plugins/kibana/public/visualize/np_ready/editor/editor.js#L374).

fyi @rayafratkina

Merging this despite missing code ownership review from Kibana App (come back home @Bargs , we miss you).

[Bargs]

@flash1293 the $scope.fetch happens outside of the conditional you linked to, so that doesn't explain that lack of a double fetch.

I dunno how long this problem has existed, but that watcher has been around since 6.x and I don't think we've been doing a double fetch for that long.

[flash1293]

Ah, you are right, the story is more complicated than that. There is also a double fetch on changing the time filter, so it might be an underlying problem. I will keep digging and test some older releases as well to pin-point it. #54526