minor fix for conversation screen title position

Session/Conversations/ConversationVC.swift

@@ -496,7 +496,7 @@ final class ConversationVC : BaseVC, ConversationViewModelDelegate, OWSConversat
                 else {
                     // Note: Adding an empty button because without it the title alignment is busted (Note: The size was
                     // taken from the layout inspector for the back button in Xcode
-                    navigationItem.rightBarButtonItem = UIBarButtonItem(customView: UIView(frame: CGRect(x: 0, y: 0, width: 37, height: 44)))
+                    navigationItem.rightBarButtonItem = UIBarButtonItem(customView: UIView(frame: CGRect(x: 0, y: 0, width: Values.verySmallProfilePictureSize, height: 44)))
                 }
             }
             else {

Session/Shared/BaseVC.swift

@@ -62,10 +62,7 @@ class BaseVC : UIViewController {
             navigationBar.barTintColor = Colors.navigationBarBackground
         }
         
-        // Back button (to appear on pushed screen)
-        let backButton = UIBarButtonItem(title: "", style: .plain, target: nil, action: nil)
-        backButton.tintColor = Colors.text
-        navigationItem.backBarButtonItem = backButton
+        navigationItem.backButtonTitle = ""
     }
 
     internal func setNavBarTitle(_ title: String, customFontSize: CGFloat? = nil) {