Disable hold-steppers option completely for Griffin-flavour.

Users could still set the option first, _then_ switch to Griffin, giving the same problems before the default was switched to false (since the setting is disabled for Griffin flavour anyway).

part of CURA-10451

plugins/PostProcessingPlugin/scripts/PauseAtHeight.py

@@ -478,6 +478,7 @@ class PauseAtHeight(Script):
                     prepend_gcode += "M117 " + display_text + "\n"
 
                 # Set the disarm timeout
+                if pause_method != "griffin":
                     if hold_steppers_on:
                         prepend_gcode += self.putValue(M = 84, S = 3600) + " ; Keep steppers engaged for 1h\n"
                     elif disarm_timeout > 0: