Key 'wandb_extra_kwargs' not in 'ExperimentConfig'

```
(benchmarl) bharath@bharath-HP-Z230-Tower-Workstation:~/marl_team/BenchMARL$ python benchmarl/run.py algorithm=mappo task=pettingzoo/simple_spread "experiment.loggers=[tensorboard]"
In 'experiment/base_experiment': ConfigKeyError raised while composing config:
Key 'wandb_extra_kwargs' not in 'ExperimentConfig'
full_key: experiment.wandb_extra_kwargs
object_type=ExperimentConfig

Set the environment variable HYDRA_FULL_ERROR=1 for a complete stack trace.
```

I got all the installations up and running, any help is appreciated.
Cheers

Start with benchmarl/run.py and the experiment/base_experiment configuration named in the error, then reproduce the command with algorithm=mappo, task=pettingzoo/simple_spread, and tensorboard logging. Trace why ExperimentConfig rejects experiment.wandb_extra_kwargs; done means the command composes successfully without the ConfigKeyError.

Written by the indexing model from the issue text.