Update to Migration 7 to 8 Guide: findByIdAndRemove

[vkarpov15]

Discussed in #15023

^{Originally posted by nelson030 November 6, 2024}
I found that in migrating from 7 -> 8 findByIdAndRemove is no longer a valid method on Mongoose models, but this is not in the migration guide doc. Just wanted to suggest adding this! :)