A default value to ward off deserialization exceptions

Happens when server side rendering is disabled.

Author: gunnim

src/React.Router/ReactRouterFunctions.cs

@@ -9,8 +9,10 @@ public class ReactRouterFunctions : RenderFunctionsBase
 	{
 		/// <summary>
 		/// The returned react router context, as a JSON string
+		/// A default value wards off deserialization exceptions
+		/// when server side rendering is disabled
 		/// </summary>
-		public string ReactRouterContext { get; private set; }
+		public string ReactRouterContext { get; private set; } = "{}";
 
 		/// <summary>
 		/// Implementation of PreRender