Include system environment variables when resolving ASPNETCORE_URLS (#107293)

Author: maraf

src/mono/wasm/host/BrowserHost.cs

@@ -68,6 +68,14 @@ private async Task RunAsync(ILoggerFactory loggerFactory, CancellationToken toke
                                                debugging: _args.CommonConfig.Debugging);
         runArgsJson.Save(Path.Combine(_args.CommonConfig.AppPath, "runArgs.json"));
 
+        // Read system environment variables after runArgs.json is saved, so they won't be passed to browser.
+        // But we need them to correctly read ASPNETCORE_URLS
+        foreach (DictionaryEntry de in Environment.GetEnvironmentVariables())
+        {
+            if (de.Key is not null && de.Value is not null)
+                envVars[(string)de.Key] = (string)de.Value;
+        }
+
         string[] urls = (envVars.TryGetValue("ASPNETCORE_URLS", out string? aspnetUrls) && aspnetUrls.Length > 0)
                             ? aspnetUrls.Split(';', StringSplitOptions.RemoveEmptyEntries)
                             : new string[] { $"http://127.0.0.1:{_args.CommonConfig.HostProperties.WebServerPort}", "https://127.0.0.1:0" };