fix: need to properly stop periodic timer/activity on destroy to eliminate possible memory leaks

MTMR/Widgets/CurrencyBarItem.swift

@@ -127,4 +127,8 @@ class CurrencyBarItem: CustomButtonTouchBarItem {
         newTitle.setAlignment(.center, range: NSRange(location: 0, length: title.count))
         attributedTitle = newTitle
     }
+    
+    deinit {
+        activity.invalidate()
+    }
 }

MTMR/Widgets/WeatherBarItem.swift

@@ -135,4 +135,8 @@ class WeatherBarItem: CustomButtonTouchBarItem, CLLocationManagerDelegate {
 //        print("inside didChangeAuthorization ");
         updateWeather()
     }
+    
+    deinit {
+        activity.invalidate()
+    }
 }

MTMR/Widgets/YandexWeatherBarItem.swift

@@ -121,6 +121,10 @@ class YandexWeatherBarItem: CustomButtonTouchBarItem, CLLocationManagerDelegate
     func locationManager(_: CLLocationManager, didChangeAuthorization _: CLAuthorizationStatus) {
         updateWeather()
     }
+    
+    deinit {
+        activity.invalidate()
+    }
 }
 
 extension String {