Limit Sidekiq args logging to 10 KB of JSON

When logging arguments from Sidekiq to JSON, restrict the size of `args`
to 10 KB (when converted to JSON). This is to avoid blowing up with
excessively large job payloads.
5 jobs for !24493 with 56547-limit-sidekiq-logging-based-on-argument-size in 29 minutes and 35 seconds (queued for 2 seconds)
detached
Status Job ID Name Coverage
  Prepare
passed #149211270
gitlab-org docker
build-qa-image

00:04:31

 
  Test
passed #149211276
gitlab-org allowed to fail
review-deploy

00:22:45

manual #149211287
gitlab-org docker allowed to fail manual
review-qa-all
passed #149211281
gitlab-org docker allowed to fail
review-qa-smoke

00:25:03

manual #149211288
gitlab-org allowed to fail manual
review-stop