only run the ButtonThread if a button is pressed

src/input/ButtonThread.cpp

@@ -274,7 +274,12 @@ int32_t ButtonThread::runOnce()
         }
     }
     btnEvent = BUTTON_EVENT_NONE;
-    return 50;
+
+    // only pull when the button is pressed, we get notified via IRQ on a new press
+    if (!userButton.isIdle() || waitingForLongPress) {
+        return 50;
+    }
+    return INT32_MAX;
 }
 
 /*