Fix json validation during serialization

[rayokota]

Ensure the schema info is updated before using it for JSON validation.

Fixes #1078

Supercedes #984

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✅ rayokota
❌ ConfluentJenkins
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[cla-assistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ rayokota
❌ ConfluentJenkins
_{You have signed the CLA already but the status is still pending? Let us recheck it.}