Users are not allowed to run addShard when in a transitional FCV due to this logic. Because transitionFromDedicatedConfigServer calls into addShard logic, that command also is not allowed to run with a transitional FCV.

I am not aware of any such restrictions for removeShard (and therefore transitionToDedicatedConfigServer). We should add test coverage of these commands while in transitional FCVs (both upgrading and downgrading).

We should add a dedicated test because we are unable to test these commands without being able to run addShard or transitionFromDedicatedConfigServer in all_commands_downgrading_to_upgraded.js.