--launch-command does not work on tcsh

[mnlevy1981]

echo '\$(hostname -f)' raises issues when tcsh tries to run this command on another shell:

[bash] $ bash -lc "echo 'jupyter lab --no-browser --ip=\$(hostname -f)'"
jupyter lab --no-browser --ip=$(hostname -f)
[bash] $ tcsh -c "echo 'jupyter lab --no-browser --ip=\$(hostname -f)'"
jupyter lab --no-browser --ip=$(hostname -f)
[tcsh] > bash -lc "echo 'jupyter lab --no-browser --ip=\$(hostname -f)'"
Variable name must contain alphanumeric characters.
[tcsh] > tcsh -c "echo 'jupyter lab --no-browser --ip=\$(hostname -f)'"
Variable name must contain alphanumeric characters.

This will cause problems when users try to use the --launch-command argument when the default shell on the remote machine is tcsh (regardless of what --shell is)