use same background color for buttons as action cells have

DcCore/DcCore/Helper/DcColors.swift

@@ -16,7 +16,7 @@ public struct DcColors {
     public static let defaultBackgroundColor = UIColor.themeColor(light: .white, dark: .black)
     public static let defaultTransparentBackgroundColor = DcColors.defaultBackgroundColor.withAlphaComponent(0.75)
     public static let defaultInverseColor = UIColor.themeColor(light: .black, dark: .white)
-    public static let sharedChatCellBackgroundColor = UIColor.themeColor(light: white, dark: actionCellBackgroundDark)
+    public static let profileCellBackgroundColor = UIColor.themeColor(light: white, dark: actionCellBackgroundDark)
     public static let chatBackgroundColor = UIColor.themeColor(light: .white, dark: .black)
     public static let checkmarkGreen = UIColor.themeColor(light: UIColor.rgb(red: 112, green: 177, blue: 92))
     public static let unreadBadge = UIColor(hexString: "3792fc")

deltachat-ios/Controller/ContactDetailViewController.swift

@@ -191,7 +191,7 @@ class ContactDetailViewController: UITableViewController {
         case .sharedChats:
             if let cell = tableView.dequeueReusableCell(withIdentifier: ContactCell.reuseIdentifier, for: indexPath) as? ContactCell {
                 viewModel.update(sharedChatCell: cell, row: row)
-                cell.backgroundColor = DcColors.sharedChatCellBackgroundColor
+                cell.backgroundColor = DcColors.profileCellBackgroundColor
                 return cell
             }
         }

deltachat-ios/View/ContactDetailHeader.swift

@@ -43,7 +43,7 @@ class ContactDetailHeader: UIView {
         let button = UIButton()
         button.translatesAutoresizingMaskIntoConstraints = false
         button.addTarget(self, action: #selector(searchBtnTapped), for: .touchUpInside)
-        button.backgroundColor = DcColors.defaultBackgroundColor
+        button.backgroundColor = DcColors.profileCellBackgroundColor
         button.setImage(UIImage(named: "ic_search")?.sd_tintedImage(with: .systemBlue), for: .normal)
         button.contentVerticalAlignment = .fill
         button.contentHorizontalAlignment = .fill
@@ -62,7 +62,7 @@ class ContactDetailHeader: UIView {
         let button = UIButton()
         button.translatesAutoresizingMaskIntoConstraints = false
         button.addTarget(self, action: #selector(muteBtnTapped), for: .touchUpInside)
-        button.backgroundColor = DcColors.defaultBackgroundColor
+        button.backgroundColor = DcColors.profileCellBackgroundColor
         if #available(iOS 13.0, *) {
             button.setImage(UIImage(systemName: "bell")?.sd_tintedImage(with: .systemBlue), for: .normal)
         } else {