update title unconditionally in CHAT_MODIFIED

this will lead to double updates as
the title is updated in viewWillAppear as well
if viewControllers atop are removed.
however, this is probably only a minor issue
and the correct way seems to be to alter viewWillAppear
as doing fewer things there and having the ViewController "ready" before coming to view
feels snappier anyway.

deltachat-ios/Chat/ChatViewController.swift

@@ -617,12 +617,7 @@ class ChatViewController: UITableViewController, UITableViewDropDelegate {
                         self.messageInputBar.isHidden = true
                     }
                 }
-
-                let oldMuted = self.navigationItem.rightBarButtonItems?.contains(self.muteItem)
-                let newMuted = self.dcChat.isMuted
-                if oldMuted != newMuted {
-                    self.updateTitle()
-                }
+                self.updateTitle()
             }
         }