truncate subtitle as needed

setContentCompressionResistancePriority() does not make sense here,
the outer avatar and back-button should have a higher priority

deltachat-ios/View/ChatTitleView.swift

@@ -37,7 +37,6 @@ class ChatTitleView: UIView {
         subtitleLabel.translatesAutoresizingMaskIntoConstraints = false
         subtitleLabel.font = UIFont.systemFont(ofSize: 12)
         subtitleLabel.textAlignment = .center
-        subtitleLabel.setContentCompressionResistancePriority(.required, for: .horizontal)
         return subtitleLabel
     }()