In its current implementation the transition between embeded <> dedicated config shard is implemented as a full-blown add/remove shard sequence, that adds and removes the config entry from config.shards and changes the topologyTime. This constitutes an implementation that is not at the highest possible architectural level and causes it to special-case add/remove shard for the config entry, leaves the ShardingState in an indeterminate state and also hits the lack of functionality related to PM-2050. Furthermore, it relies on a scenario that we don't support today and probably won't support in the future, which is re-adding a shard after having removed it.

This ticket is to simplify this transition to just be equivalent to a balancer hint, to not place any new data on the config shard and to move any data already placed plus some ability to know when that movement has completed.