Also log episodic_length for non-PPO scripts.

[vwxyzjn]

Problem Description

We should also log episodic_length for non-PPO scripts. That is we do the following for PPO

cleanrl/cleanrl/ppo.py

Lines 213 to 214 in 5184afc

	writer.add_scalar("charts/episodic_return", item["episode"]["r"], global_step)
	writer.add_scalar("charts/episodic_length", item["episode"]["l"], global_step)

but in dqn.py we don't do this:

cleanrl/cleanrl/dqn.py

Lines 167 to 170 in 5184afc

	for info in infos:
	if "episode" in info.keys():
	print(f"global_step={global_step}, episodic_return={info['episode']['r']}")
	writer.add_scalar("charts/episodic_return", info["episode"]["r"], global_step)