[algo] fix: strip '+' suffix in kl_penalty so k3+/low_var_kl+ work#6058

tongyx361 merged 1 commit intoverl-project:mainverl-project/verl:mainfrom

MaxwellJryao:fix/kl-penalty-plus-suffixMaxwellJryao/verl:fix/kl-penalty-plus-suffixCopy head branch name to clipboard