The issue with the `sharding_csrs_continuous_config_stepdown` suite is that the stepdown thread hangs when we run config transitions at the end of the test. This occurs because the stepdown thread continues to run even after the config shard replica set has been stopped.

The reason why this happens is because:

• The stepdown thread is only stopped when stopSet() is called on the this.configRS variable.
• But in config shard mode, stopSet() is never called on this.configRS variable as the config shard was already stopped here in the call to stopAllShards().

The goal of this ticket is to ensure that config transitions are compatible with the `sharding_csrs_continuous_config_stepdown` suite.

One possible solution is to modify the ShardingTest so that it does not stop the config shard in `stopAllShards()`, and instead stops it separately using `stopAllConfigServers()`.