Consider replacing Section 1.4.2 with a reference to the Subscriber Agreement

[aarongable]

See https://community.letsencrypt.org/t/inconsistency-between-subscriber-agreement-and-the-cp-cps/215079 for an example of how the language in the Subscriber Agreement and the language in the CP/CPS differ here.

We have other sections which reference the SA with regard to Subscriber behavior, such as Section 4.5.1: https://github.com/letsencrypt/cp-cps/blob/177a3e3daf88561e3c5e77faa9fbfaaf62a474d3/CP-CPS.md?plain=1#L352-L354

The BRs do not place any requirements on the contents of this section. So I think we can, and should, follow a similar model here.