Hide env variables `GPTSCRIPT_LIST_MODELS` and` GPTSCRIPT_LIST_TOOLS` from `help` text.

[sangee2004]

Following env variables GPTSCRIPT_LIST_MODELS and GPTSCRIPT_LIST_TOOLS are exposed in help text.

      --list-models                 List the models available and exit ($GPTSCRIPT_LIST_MODELS)
      --list-tools                  List built-in tools and exit ($GPTSCRIPT_LIST_TOOLS)

It is not obvious how these env variables can be used . Can these variables be removed from the help if they do not provide any additional value to users .