use disabled state for lowDataMode

Co-authored-by: bjoern <r10s@b44t.com>

deltachat-ios/Controller/ConnectivityViewController.swift

@@ -115,7 +115,7 @@ class ConnectivityViewController: WebViewViewController {
         }
 
         if isLowDataMode {
-            return "<span class=\"red dot\"></span>"
+            return "<span class=\"disabled dot\"></span>"
                 .appending(title)
                 .appending(String.localized("connectivity_low_data_mode"))
         }