gcode: Automatically call reset_last_position() on a toolhead set_position()

Generate a "toolhead:set_position" event on a call to
toolhead.set_position() and use that event to automatically call
gcode.reset_last_position().

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/extras/probe.py

@@ -123,7 +123,6 @@ class PrinterProbe:
         pos = toolhead.get_position()
         self.gcode.respond_info("probe at %.3f,%.3f is z=%.6f"
                                 % (pos[0], pos[1], pos[2]))
-        self.gcode.reset_last_position()
         return pos[:3]
     def _move(self, coord, speed):
         toolhead = self.printer.lookup_object('toolhead')