toolhead: Don't raise exception from force_shutdown

Catch and ignore any exceptions when trying to shutdown the printer in
toolhead.force_shutdown() - there's a good chance an exception will be
raised as this method is often called after an invalid internal state
is found.

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

klippy/toolhead.py

@@ -365,6 +365,9 @@ class ToolHead:
         return "print_time=%.3f buffer_time=%.3f print_stall=%d" % (
             print_time, buffer_time, self.print_stall)
     def force_shutdown(self):
+        try:
             self.printer.mcu.force_shutdown()
             self.move_queue.reset()
             self.reset_print_time()
+        except:
+            logging.exception("Exception in force_shutdown")