fix nested transaction crash

Session/Notifications/AppNotifications.swift

@@ -174,7 +174,7 @@ public class NotificationPresenter: NSObject, NotificationsProtocol {
         }
 
         let context = Contact.context(for: thread)
-        let senderName = Storage.shared.getContact(with: incomingMessage.authorId)?.displayName(for: context) ?? incomingMessage.authorId
+        let senderName = Storage.shared.getContact(with: incomingMessage.authorId, using: transaction)?.displayName(for: context) ?? incomingMessage.authorId
 
         let notificationTitle: String?
         switch previewType {

SessionMessagingKit/Database/Storage+Contacts.swift

@@ -7,8 +7,16 @@ extension Storage {
     public func getContact(with sessionID: String) -> Contact? {
         var result: Contact?
         Storage.read { transaction in
-            result = transaction.object(forKey: sessionID, inCollection: Storage.contactCollection) as? Contact
+            result = self.getContact(with: sessionID, using: transaction)
+        }
+        return result
     }
+    
+    @objc(getContactWithSessionID:using:)
+    public func getContact(with sessionID: String, using transaction: Any) -> Contact? {
+        var result: Contact?
+        let transaction = transaction as! YapDatabaseReadTransaction
+        result = transaction.object(forKey: sessionID, inCollection: Storage.contactCollection) as? Contact
         if let result = result, result.sessionID == getUserHexEncodedPublicKey() {
             result.isTrusted = true // Always trust ourselves
         }