Log servers might not be checked when using locality based exclusion

The intention of this issue is to create visibility for the limitation mentioned in https://github.com/apple/foundationdb/pull/11009. We update the documentation to reflect this limitation, but I think it's good to have an issue to track to fix for this.

TLDR: If a log process is not running (reporting to the worker list), it will be missed by the locality based exclusions and there will be no validation if the mutation of this log process are already persisted. This is only true for the blocking of the `exclude` command, the actual exclusion is still happening in the background.

Start by reading the limitation documented in PR #11009 and trace the locality-based exclusion path for log processes missing from the worker list. Reproduce the blocking `exclude` case and identify how mutation persistence is validated; done means offline log processes are checked before blocking while background exclusion still proceeds.

Written by the indexing model from the issue text.