add json validation for sdk

This CL is a follow up of https://flutter-review.googlesource.com/c/recipes/+/6140, to add json validation logic for all sdk recipes.

Bug: https://github.com/flutter/flutter/issues/64366
Change-Id: I3f0db7f953bad2216a8b6da692e0892352ac41c5
Reviewed-on: https://flutter-review.googlesource.com/c/recipes/+/6181
Reviewed-by: Godofredo Contreras <godofredoc@google.com>
Commit-Queue: Keyong Han <keyonghan@google.com>