fix(notification): body should be optional on iOS (#1737)

.changes/notification-body-optional-ios.md

@@ -0,0 +1,5 @@
+---
+"notification": patch
+---
+
+The notification body is now optional on iOS to match the other platforms.

plugins/notification/ios/Sources/Notification.swift

@@ -32,9 +32,11 @@ func makeNotificationContent(_ notification: Notification) throws -> UNNotificat
   let content = UNMutableNotificationContent()
   content.title = NSString.localizedUserNotificationString(
     forKey: notification.title, arguments: nil)
+  if let body = notification.body {
     content.body = NSString.localizedUserNotificationString(
-    forKey: notification.body,
+      forKey: body,
       arguments: nil)
+  }
 
   content.userInfo = [
     "__EXTRA__": notification.extra as Any,

plugins/notification/ios/Sources/NotificationPlugin.swift

@@ -65,7 +65,7 @@ struct NotificationAttachment: Codable {
 struct Notification: Decodable {
   let id: Int
   var title: String
-  var body: String
+  var body: String?
   var extra: [String: String]?
   let schedule: NotificationSchedule?
   let attachments: [NotificationAttachment]?