remove unused imports and variables

deltachat-ios/Chat/ChatViewController.swift

@@ -7,8 +7,6 @@ import SDWebImage
 
 class ChatViewController: UITableViewController, UITableViewDropDelegate {
     var dcContext: DcContext
-    let outgoingAvatarOverlap: CGFloat = 17.5
-    let loadCount = 30
     let chatId: Int
     var messageIds: [Int] = []
 

deltachat-ios/Extensions/Extensions.swift

@@ -1,8 +1,6 @@
 import UIKit
 import Foundation
 import CommonCrypto
-import UniformTypeIdentifiers
-import MobileCoreServices
 
 extension Dictionary {
     func percentEscaped() -> String {