Fixes setting the seed from CLI for RSL-RL (#1084)

# Description

This pull request fixes a bug that prevented setting the seed from CLI
arguments. The issue was caused by an extra pair of quotation marks in
the `hasattr` check for `args_cli`. Removing these allows the seed to be
correctly set via CLI.

## Type of change

- Bug fix (non-breaking change which fixes an issue)

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

CONTRIBUTORS.md

@@ -47,6 +47,7 @@ Guidelines for modifications:
 * Jia Lin Yuan
 * Jingzhou Liu
 * Johnson Sun
+* Kaixi Bao
 * Kourosh Darvish
 * Lorenz Wellhausen
 * Masoud Moghani

source/standalone/workflows/rsl_rl/cli_args.py

@@ -67,7 +67,7 @@ def update_rsl_rl_cfg(agent_cfg: RslRlOnPolicyRunnerCfg, args_cli: argparse.Name
         The updated configuration for RSL-RL agent based on inputs.
     """
     # override the default configuration with CLI arguments
-    if hasattr("args_cli", "seed") and args_cli.seed is not None:
+    if hasattr(args_cli, "seed") and args_cli.seed is not None:
         agent_cfg.seed = args_cli.seed
     if args_cli.resume is not None:
         agent_cfg.resume = args_cli.resume