replace duplicated method

DcCore/DcCore/DC/Wrapper.swift

@@ -250,10 +250,6 @@ public class DcContext {
         return DcArray(arrayPointer: dc_get_fresh_msgs(contextPointer))
     }
 
-    public func getFreshMessagesCount(chatId: Int) -> Int {
-        return Int(dc_get_fresh_msg_cnt(contextPointer, UInt32(chatId)))
-    }
-
     public func markSeenMessages(messageIds: [UInt32]) {
         messageIds.withUnsafeBufferPointer { ptr in
             dc_markseen_msgs(contextPointer, ptr.baseAddress, Int32(ptr.count))

deltachat-ios/Chat/ChatViewController.swift

@@ -776,7 +776,7 @@ class ChatViewController: UITableViewController {
 
         // update message ids
         self.messageIds = self.getMessageIds()
-        let freshMsgsCount = self.dcContext.getFreshMessagesCount(chatId: self.chatId)
+        let freshMsgsCount = self.dcContext.getUnreadMessages(chatId: self.chatId)
         if freshMsgsCount > 0 && self.messageIds.count >= freshMsgsCount {
             let index = messageIds.count - freshMsgsCount
             freshMessageIndex = IndexPath(row: index, section: 0)
@@ -811,7 +811,7 @@ class ChatViewController: UITableViewController {
     private func scrollToLastUnseenMessage() {
         DispatchQueue.main.async { [weak self] in
             guard let self = self else { return }
-            let freshMsgsCount = self.dcContext.getFreshMessagesCount(chatId: self.chatId)
+            let freshMsgsCount = self.dcContext.getUnreadMessages(chatId: self.chatId)
             if freshMsgsCount > 0 && self.messageIds.count >= freshMsgsCount {
                 let index = self.messageIds.count - freshMsgsCount
                 let indexPath = IndexPath(row: index, section: 0)