return empty string if no version

Author: minestarks

Nodejs/Product/Nodejs/Project/ImportWizard/ImportSettings.cs

@@ -554,7 +554,7 @@ private static string GetLatestAvailableTypeScriptVersionFromSetup()
                     .First();
             }
 
-            return null;
+            return "";
         }
     }
 }

Nodejs/Product/ProjectWizard/NodejsPackageParametersExtension.cs

@@ -90,7 +90,7 @@ private static string GetLatestAvailableTypeScriptVersionFromSetup()
                     .First();
             }
 
-            return null;
+            return "";
         }
     }
 }