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

dns/ViewModel.swift

@@ -17,7 +17,12 @@ class ViewModel: NSObject, ObservableObject {
         didSet {
             Settings.blocklist = blocklist
 
-            toggleDns()
+            if isDnsEnabled {
+                toggleDns()
+            }
+            else {
+                isProgrammaticChange = false
+            }
         }
     }