Clarify whether we recommend to have a CI environment separate from prod

### Contributions

- [X] I have read the contribution docs, and understand what's expected of me.

### Link to the page on docs.getdbt.com requiring updates

https://docs.getdbt.com/docs/deploy/ci-jobs
https://docs.getdbt.com/guides/set-up-ci?step=2
(other ones?)

### What part(s) of the page would you like to see updated?

I thought that we had to create CI environments different from the Prod one in order not to get Metadata/Discovery not loading metadata from those runs but [this thread](https://dbt-labs.slack.com/archives/CSSHB76QL/p1713779133289659?thread_ts=1713292024.668929&cid=CSSHB76QL) with @jtcohen6 mentions that it is not required for jobs defined as CI ones.

We should clarify:
1. whether we recommend a different CI environment or not
2. and that there is some special logic happening with the CI jobs that make them not being ingested by the Metadata/Discovery process

### Additional information

_No response_