[8.x](backport #42271) x-pack/metricbeat/module/sql: Add debug queries when merge_results: true

[mergify]

Proposed commit message

Add debug queries when merge_results: true. No new configuration added to match the behaviour when merge_results: false. Previously, as it was multiple queries that results in merge of results, the query parameter was left entry and hence the field was omitted out when merge_results: true. Now, we will publish it from here. Users that want this can keep it and others who do not want it can drop it.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

How to test this PR locally

• Test if queries are there when merge_results is set to true.

Related issues

• SQL server integration provide the sql.query for debug integrations#12029
• [O11y][MSSQL] Add mssql.query field to transaction_logs data stream for debug purposes integrations#12216
• [Don't Merge][O11y][MSSQL] Remove unnecessary processor in performance data stream integrations#12212

Screenshots

• When merge_results: false:

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• When merge_results: true:

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This is an automatic backport of pull request #42271 done by [Mergify](https://mergify.com).