Change instance type back after HOC

[jeremydstone]

This changes our production front end instance type from r4.8xlarge (higher memory instance type we were running during hour of code) to m4.10xlarge, the less expensive instance type we normally run.

[wjordan]

Instance-type change LGTM.

I had made some changes in #19379 that might make this change not longer be applied without an extra manual tweak to an existing parameter. I'll keep an eye out to make sure this change gets applied correctly when it's deployed.

[wjordan]

I've applied the necessary manual tweak to the InstanceType parameter in the production config, so the instance type will be changed on the next production deploy.