Fix to scroll to first unread message

Signed-off-by: Marcel Hibbe <dev@mhibbe.de>

app/src/main/java/com/nextcloud/talk/chat/ChatActivity.kt

@@ -2523,7 +2523,16 @@ class ChatActivity :
         addMessagesToAdapter(shouldAddNewMessagesNotice, chatMessageList)
 
         if (shouldAddNewMessagesNotice && adapter != null) {
-            layoutManager?.scrollToPosition(0)
+            scrollToFirstUnreadMessage()
+        }
+    }
+
+    private fun scrollToFirstUnreadMessage() {
+        adapter?.let {
+            layoutManager?.scrollToPositionWithOffset(
+                it.getMessagePositionByIdInReverse("-1"),
+                binding.messagesListView.height / 2
+            )
         }
     }