Issue #3: Only change system setting immediately, if isDnsEnabled.

dns/ViewModel.swift

@@ -17,8 +17,13 @@ class ViewModel: NSObject, ObservableObject {
         didSet {
             Settings.blocklist = blocklist
 
+            if isDnsEnabled {
                 toggleDns()
             }
+            else {
+                isProgrammaticChange = false
+            }
+        }
     }
 
     @Published