servers_no_promotion should prevent a server from being promoted due to replication change

The setting name sounds as if it would prevent any kind of master server promotion. This was not the case, as the setting only affected switchover/failover new master autoselection. Although this was documented, it is unintuitive and confusing. The functionality should be changed so that master selection due to replication/read_only changes is also prevented for servers listed in servers_no_promotion. Manual promotion by switchover is still allowed by specifying the server name in the command.

Original description:
Customer would like servers_no_promotion to be able to prevent promotion whether it would be triggered by database/replication changes, failover itself, or another event.