Stringify Sidekiq job args in exception logs

If these logs are sent to Elasticsearch, it will not be able to process nested object fields, as this causes a type mismatch with scalar elements in the same array across log lines.

This was done in !26267 (merged), but that change did not apply to Sidekiq exceptions.

We also move all Sidekiq agument formatting into the JSON formatter. This puts the formatting of job logs in one place and avoids the pitfalls of altering job arguments in the actual payload.

Closes #213639 (closed)