First part of a solution for fixing JSON validation security issue

[david0xd]

First part to fix an issue around JSON validation.

Second part (PR): MetaMask/snaps#1405

Explanation

This PR resolves the security issue with JSON validation and usage of the validated objects.

JsonStruct is updated to use coerce instead of define and it does sanitization now by having JSON.parse(JSON.stringify(value)) as the return value.
From now it is supposed that validation is done using create function from Superstruct which will return validated and sanitized JSON. New function getValidatedAndSanitizedJson which handles this is added.

isValidJson function is updated in order to use new JsonStruct and keep its return values the same.

On the places (e.g. snaps-monorepo) where JSON structure is validated and used later in the process, getValidatedAndSanitizedJson should always be used.

[ritave]

We should merge all parts of this task at the same time so as not to have a release with unsafe JSON.

[hmalik88]

LGTM

[ritave]

minor stylistical