Throwing exception with null message in non-HTTP trigger causing functions host crash

Throwing exception with null message in non-HTTP trigger causing functions host crash.

This is the related log from local debug func tool.

```
[2022-01-17T13:19:29.939Z] Executing 'NullMessageExceptionInQueue' (Reason='New queue message detected on 'test-exception-queue'.', Id=e891a2b4-f1df-4711-8e4c-090d8300617f)
[2022-01-17T13:19:29.940Z] Trigger Details: MessageId: 5afed3b7-1b0a-44a8-acd6-8a382878270b, DequeueCount: 1, InsertedOn: 2022-01-17T13:19:28.000+00:00
[2022-01-17T13:19:30.657Z] Host lock lease acquired by instance ID '000000000000000000000000618DFF3B'.
[2022-01-17T13:19:31.064Z] An unhandled exception has occurred. Host is shutting down.
[2022-01-17T13:19:31.065Z] Microsoft.Azure.WebJobs.Script: Object reference not set to an instance of an object.
```

#### Repro steps

Calling function NullMessageException and wait for crash.

```csharp
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.Extensions.Logging;
using System;
using System.Threading.Tasks;

namespace MyFunctions
{
public static class NullMessageException
{
[FunctionName("NullMessageException")]
public static async Task Run(
[HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
[Queue("test-exception-queue", Connection = "AzureWebJobsStorage")] IAsyncCollector queue,
ILogger log)
{
await queue.AddAsync("hello");
await queue.FlushAsync();
return new AcceptedResult();
}

[FunctionName("NullMessageExceptionInQueue")]
public static async Task Run2(
[QueueTrigger("test-exception-queue", Connection = "AzureWebJobsStorage")] string exceptionQueue,
ILogger log)
{
await Task.Delay(1000);
throw new CustomException();
}

private class CustomException : Exception
{
public override string Message => null;
}
}
}
```

#### Expected behavior

Poisoning the queue item.

#### Actual behavior

Function host crashed.

#### Related information

I found this by instantiating a Microsoft.Azure.Cosmos.CosmosException with null message and then throw, this takes me two days to understand why my code caused tools host to crash...