Update route handling to modify existing routes instead of duplicating

VirtualDDNSRouter.Server/Program.cs

@@ -42,12 +42,21 @@ app.MapGet("/setip/{path}/{port}/{apiKey}", async (IYamlParser yamlParser ,HttpC
         app.Logger.LogInformation($"Could not get the client ip address for {path} with port {port}.");       
         return Results.BadRequest("Could not get the client ip address");
     }
-    routes.Add(new Route
+    var existingRoute = routes.FirstOrDefault(r => r.path == path);
+    if (existingRoute is not null)
     {
-        ipAddress = clientIp,
-        path = path,
-        port = port
-    });
+        existingRoute.ipAddress = clientIp;
+        existingRoute.port = port;
+    }
+    else
+    {
+        routes.Add(new Route
+        {
+            ipAddress = clientIp,
+            path = path,
+            port = port
+        });
+    }
     return Results.Ok($"goto/{path}");
 });