Smaller issue with invalid commands and help output

[thschmitt]

Two smaller issues when typing some unknown commands:

1. When using an invalid service name like uipath unknown the help output does not show all available commands, e.g.

COMMANDS:
   autocomplete  Autocompletion
   config        Interactive Configuration

2. When typing an invalid operation name, e.g. uipath du unknown, the error message is confusing and we should rather show the help output:

No help topic for 'unknown'