fix issue with fixture value in feature file, when the value is dict

[eliram]

. . An example of good pull request names: . - Add Russian translation (fixes #123) . - Add an ability to disable default plugins . - Support emoji in test descriptions )

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Checklist

• [x] Sign Allure CLA
• [x] Provide unit tests

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Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

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