Fix IsUnpackaged extension to include UnpackedDotnetFirstSignalR

src/ElectronNET.API/Common/Extensions.cs

@@ -14,6 +14,7 @@ namespace ElectronNET.Common
             {
                 case StartupMethod.UnpackedElectronFirst:
                 case StartupMethod.UnpackedDotnetFirst:
+                case StartupMethod.UnpackedDotnetFirstSignalR:
                     return true;
                 default:
                     return false;