Avoid redrawing 'powered off' redundantly.

If the power state stays the same between queries, take no action to clear screen and
draw redundant data.

In the case of misreporting devices, it mitigates the impact of incorrect reporting,
while generally preserving the output behavior when accurate.

confluent_client/bin/confetty

@@ -948,8 +948,9 @@ def main():
                     except IOError:
                         pass
             if powerstate is None or powertime < time.time() - 10:  # Check powerstate every 10 seconds
+                if powerstate == None:
+                    powerstate = True
                 powertime = time.time()
-                powerstate = True
                 check_power_state()
         else:
             currcommand = prompt()