fix resetting chat cells for reuse

deltachat-ios/Chat/Views/Cells/FileTextCell.swift

@@ -25,6 +25,7 @@ class FileTextCell: BaseMessageCell {
     }
 
     override func prepareForReuse() {
+        super.prepareForReuse()
         fileView.prepareForReuse()
     }
 

deltachat-ios/Chat/Views/Cells/ImageTextCell.swift

@@ -164,6 +164,7 @@ class ImageTextCell: BaseMessageCell {
     }
 
     override func prepareForReuse() {
+        super.prepareForReuse()
         contentImageView.image = nil
         contentImageView.sd_cancelCurrentImageLoad()
         tag = -1

deltachat-ios/Chat/Views/Cells/InfoMessageCell.swift

@@ -61,4 +61,10 @@ class InfoMessageCell: UITableViewCell {
         messageBackgroundContainer.update(rectCorners: corners, color: DcColors.systemMessageBackgroundColor)
     }
 
+    override func prepareForReuse() {
+        super.prepareForReuse()
+        messageLabel.text = nil
+        messageLabel.attributedText = nil
+    }
+
 }