[data.search] Fix format of CCS timed out responses

[lukasolson]

Summary

@jughosta noticed in https://github.com/elastic/kibana/pull/179679#issuecomment-2079492811 that when modifying the response format after we hit a time out, we weren't properly setting the timed_out flag to true on the entire response object, just on the individual clusters. This PR fixes that behavior.

Checklist

• [x] Unit or functional tests were updated or added to match the most common scenarios

[lukasolson]

/ci

[elasticmachine]

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

[kibana-ci]

:yellow_heart: Build succeeded, but was flaky

• Buildkite Build
• Commit: b708070e4ac6c4a62a83fe6d22906bc2c2d92d4d

Failed CI Steps

• FTR Configs #30

Test Failures

• [job] [logs] FTR Configs #30 / alerting api integration security and spaces enabled Alerts - Group 1 alerts find Actions should return the actions correctly

Metrics [docs]

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
data	418.5KB	418.5KB	+13.0B

History

• :green_heart: Build #206994 succeeded 2050790495c1d98142a4ef160267675d1a2a3d1b
• :yellow_heart: Build #206468 was flaky 40024858b05cc3e39a1e08f10f4425c8098656eb

To update your PR or re-run it, just comment with: @elasticmachine merge upstream

cc @lukasolson