fix activity() to immediately un-dim screen

Author: jepler

adafruit_pybadger/pybadger_base.py

@@ -430,6 +430,10 @@ def auto_dim_display(self, delay: float = 5.0, movement_threshold: int = 10):
             self.display.brightness = self._display_brightness
 
     def activity(self, current_time=None):
+        """Turn postpone dimming of the screen"""
+        if not hasattr(self.display, "brightness"):
+            return
+        self.display.brightness = self._display_brightness
         self._start_time = current_time or time.monotonic()
 
     @property