Reduce the chattiness of agents calling CAPI (e.g. Deeply Read, Most Read) in CODE and Preview

[SiAdcock]

We suspect that agents calling CAPI in Preview, especially in the CODE environment, is responsible for the termination and cycling of Preview instances. Making too many calls to CAPI from CODE Preview causes CAPI to respond with errors, and can cause our own circuit breaker to kick in.

There's an argument about whether these agents even need to run in Preview. It's unclear there is any real value in showing an accurate Deeply Read component in articles rendered in Preview.

There's also a related question about whether the Deeply Read agent needs to make so many calls to CAPI. This would be worth investigating.