T16599 pg groupby broken

[niden]

Hello!

• Type: bug fix
• Link to issue: [BUG]: Query builder wrong assumption GROUP BY should contain model columns (Postgres) #16599

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• I have read and understood the Contributing Guidelines
• I have checked that another pull request for this purpose does not exist
• I wrote some tests for this PR
• I have updated the relevant CHANGELOG
• I have created a PR for the documentation about this change

Fixed Phalcon\Mvc\Model\Query\Builder::autoescape() incorrectly wrapping function expressions (e.g. DATE_PART(...)) in brackets when used in groupBy(), causing a "Column does not belong to any of the selected models" exception

Thanks