Fix: current_command_args contains command

@thinkyhead
Hi Scott,
your code from a0f362c7@thinkyhead is great, but you forgot to skip the
command.
Symptom `M117 Test`shows `M117 Test` on LCD instead of `Test`.

see also
https://github.com/MarlinFirmware/Marlin/commit/a0f362c735401ebbcd95de3f
6f8e3c2f17ecc770 lines 941, 2851 and so on

Greetings and welcome back

Jochen