fix: Unescape JSON strucutred metadata string values

[hvenev]

In the case of strings, ObjectEach strips the quotes but does not unescape them.

What this PR does / why we need it: Fixes #13918

Which issue(s) this PR fixes: Fixes #13918

Special notes for your reviewer:

Checklist

• [X] Reviewed the CONTRIBUTING.md guide (required)
• [ ] Documentation added
• [X] Tests updated
• [X] Title matches the required conventional commits format, see here

[CLAassistant]

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[0x006EA1E5]

Hi @hvenev I am having a similar problem to you.

Is your fix available as a docker build anywhere, to test?