allow for no monitoring url in settings

Author: PhilBastian

src/ServicePulse/ConstantsFile.cs

@@ -19,7 +19,7 @@ public static string GetContent(Settings settings)
         else
         {
             serviceControlUrl = settings.ServiceControlUri.ToString();
-            monitoringUrl = settings.MonitoringUri.ToString();
+            monitoringUrl = settings.MonitoringUri?.ToString() ?? "!";
         }
 
         var constantsFile = $$"""

src/ServicePulse/Settings.cs

@@ -6,7 +6,7 @@ class Settings
 {
     public required Uri ServiceControlUri { get; init; }
 
-    public required Uri MonitoringUri { get; init; }
+    public required Uri? MonitoringUri { get; init; }
 
     public required string DefaultRoute { get; init; }
 
@@ -36,7 +36,7 @@ public static Settings GetFromEnvironmentVariables()
         monitoringUrl ??= monitoringUrls;
         monitoringUrl ??= "http://localhost:33633/";
 
-        var monitoringUri = new Uri(monitoringUrl);
+        var monitoringUri = monitoringUrl == "!" ? null : new Uri(monitoringUrl);
 
         var defaultRoute = Environment.GetEnvironmentVariable("DEFAULT_ROUTE") ?? "/dashboard";