Parse markdown and html from push notifications (#1688)

* Extract notification content building outside of the NotificationItemProxy. First step in a bigger refactoring of the NSE

* Import the attributed string buider into the NSE, sort `sources` imports

* Extract message event string building into the RoomMessageEventStringBuilder and reuse it building content for push notifications

* Cleanup

* Add changelog

ElementX/Sources/Screens/Settings/NotificationSettingsScreen/NotificationSettingsScreenViewModel.swift

@@ -209,3 +209,9 @@ class NotificationSettingsScreenViewModel: NotificationSettingsScreenViewModelTy
         state.applyingChange = false
     }
 }
+
+extension UNUserNotificationCenter {
+    func authorizationStatus() async -> UNAuthorizationStatus {
+        await notificationSettings().authorizationStatus
+    }
+}