`--env-file-if-exists` is in the wrong spot in the docs

### Affected URL(s)

https://nodejs.org/docs/latest/api/cli.html#--env-file-if-existsconfig

### Description of the problem

Because the flag was originally `--optional-env-file` I forgot to move it after renaming it, so it is still in that spot in the documentation. It should be placed right under `--env-file` instead, and should be an extremely easy fix.

Related #53060  