…24795)

Fixes elastic#223990

## Summary

This PR fixes the forward-compatibility test for index mode, which
failed because the index mode was added to Get Data Streams API in 8.19
and 9.1 (see elastic/elasticsearch#122486), so
if Kibana 8.19 is run with Es 9.0, the index mode is always displayed as
"Standard" because Es doesn't return an index mode field.

In this PR, we separate all index mode-related tests into a separate
file, and only run it for Es versions 8.19 or 9.1+.

This was also fixed for functional tests in
elastic#223129

---------

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>
(cherry picked from commit 493ca9f)

# Conflicts:
#	x-pack/platform/test/api_integration/apis/management/index_management/data_streams.ts

…24795) (#225641)

# Backport

This will backport the following commits from `main` to `8.19`:
- [[Data Streams] Fix forward-compatibility api test failures
(#224795)](#224795)

<!--- Backport version: 10.0.1 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sorenlouv/backport)

<!--BACKPORT [{"author":{"name":"Sonia Sanz
Vivas","email":"sonia.sanzvivas@elastic.co"},"sourceCommit":{"committedDate":"2025-06-25T11:55:46Z","message":"[Data
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https://github.com/elastic/kibana/issues/223990\n\n## Summary\n\nThis PR
fixes the forward-compatibility test for index mode, which\nfailed
because the index mode was added to Get Data Streams API in 8.19\nand
9.1 (see elastic/elasticsearch#122486), so\nif
Kibana 8.19 is run with Es 9.0, the index mode is always displayed
as\n\"Standard\" because Es doesn't return an index mode field.\n\nIn
this PR, we separate all index mode-related tests into a separate\nfile,
and only run it for Es versions 8.19 or 9.1+.\n\nThis was also fixed for
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fixes the forward-compatibility test for index mode, which\nfailed
because the index mode was added to Get Data Streams API in 8.19\nand
9.1 (see elastic/elasticsearch#122486), so\nif
Kibana 8.19 is run with Es 9.0, the index mode is always displayed
as\n\"Standard\" because Es doesn't return an index mode field.\n\nIn
this PR, we separate all index mode-related tests into a separate\nfile,
and only run it for Es versions 8.19 or 9.1+.\n\nThis was also fixed for
functional tests
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https://github.com/elastic/kibana/issues/223990\n\n## Summary\n\nThis PR
fixes the forward-compatibility test for index mode, which\nfailed
because the index mode was added to Get Data Streams API in 8.19\nand
9.1 (see elastic/elasticsearch#122486), so\nif
Kibana 8.19 is run with Es 9.0, the index mode is always displayed
as\n\"Standard\" because Es doesn't return an index mode field.\n\nIn
this PR, we separate all index mode-related tests into a separate\nfile,
and only run it for Es versions 8.19 or 9.1+.\n\nThis was also fixed for
functional tests
in\nhttps://github.com//pull/223129\n\n---------\n\nCo-authored-by:
kibanamachine
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BACKPORT-->

---------

Co-authored-by: Damian Polewski <125268832+damian-polewski@users.noreply.github.com>
Co-authored-by: Damian Polewski <damian.polewski@elastic.co>