sshcontroller: Print collected output on command error

[auscompgeek]

On deploy, the Python script from get_rio_py_packages can sometimes fail, likely due to a MemoryError when deploying to a roboRIO 1.

robotpy-installer/robotpy_installer/roborio_utils.py

Lines 92 to 100 in 44fdc6d

	def get_rio_py_packages(ssh: SshController) -> typing.Dict[str, str]:
	# Use importlib.metadata instead of pip because it's way faster than pip
	result = ssh.exec_cmd(
	"/usr/local/bin/python3 -c "
	"'from importlib.metadata import distributions;"
	"import json; import sys; "
	"json.dump({dist.name: dist.version for dist in distributions()},sys.stdout)'",
	get_output=True,
	)

Print the error message from the robot in this scenario.

[auscompgeek]

One of my team members got another JSONDecodeError from get_rio_py_packages just yesterday. Does this look reasonable to you @virtuald?