Double-serialization of string as input to durable activities

[andystaples]

When sending a string as an input to a Durable activity, we get double serialization - "Seattle" becomes ""Seattle""

Code:

 @FunctionName("HelloCities")
 public List<String> runOrchestrator(
 @DurableOrchestrationTrigger(name = "context") TaskOrchestrationContext ctx, 
 final ExecutionContext context) {
 return ctx.callActivity("SayHello", "Seattle", String.class).await();
 }

 @FunctionName("SayHello")
 public String sayHello(
 @DurableActivityTrigger(name = "name") String name,
 final ExecutionContext context) {
 context.getLogger().info("Saying hello to " + name + ".");
 return "Hello " + name + "!";
 }

Returns "Hello "Seattle""