Remove replay_dry_run condition for replay_dir (#1126)

### TL;DR

Removed the conditional logic that sets `replay_dir` to `None` when
`replay_dry_run` is `True`.

### What changed?

Removed the code block that was checking for
`cfg.trainer.get("replay_dry_run", False)` and setting `replay_dir` to
`None` if that condition was true. This means that `replay_dir` will now
always be set to the path constructed from `cfg.replay_job.replay_dir`
and `cfg.run`.


[Asana
Task](https://app.asana.com/1/1209016784099267/project/1210348820405981/task/1210631127945425)

Author: daveey

mettascope/replays.py

@@ -66,8 +66,6 @@ def create_simulation(cfg):
 
         sim_name = sim_config.env.split("/")[-1]
         replay_dir = f"{cfg.replay_job.replay_dir}/{cfg.run}"
-        if cfg.trainer.get("replay_dry_run", False):
-            replay_dir = None
 
         sim = Simulation(
             sim_name,