fix(confix): wrong key set using set command

[julienrbrt]

Description

I was using confix set with a chain, and noticed it had a small issue when setting a key in a block.
This small PR fix it.

Noticed as well that swagger was not up-to-date. Done that here too.
Should we have a job that verify that and checks the diff?

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Author Checklist

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I have...

• included the correct type prefix in the PR title
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• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
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• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
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• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)