mgmt: updatehub: Fix json arrays

After the changes introduced by #50816 the UpdateHub could not decode
anymore the JSON object. This introduce missing parsing definitions
to allow JSON parser undertood the correct UpdateHub probe object.

Fixes #69297

Signed-off-by: Gerson Fernando Budke <gerson.budke@ossystems.com.br>
(cherry picked from commit 5fb62ca9)