AWS permissions issues hiddden in csharp logs

**Describe the bug**
Was just working with @sushantmimani on https://github.com/godaddy/asherah/issues/260 and ran into an incidental issue. In setting up the test code, a permission was missed, but Asherah only emitted a null object reference, nothing about the cause.

```
Object reference not set to an instance of an object.
at GoDaddy.Asherah.AppEncryption.Persistence.DynamoDbMetastoreImpl.LoadLatest(String keyId)
at GoDaddy.Asherah.AppEncryption.Envelope.EnvelopeEncryptionJsonImpl.LoadLatestKeyRecord(String keyId)
```

**To Reproduce**
Remove permission to AWS DynamoDB in csharp

**Expected behavior**
Clear message or rethrow of AWS exception.

**Screenshots**
Sushant Mimani 2 hours ago
> i can see access issue logs in cloudwatch when i remove DynamoDB perms from my role
> Also, from what i can see, the logging varies slightly for Java and C#. The above trace was from the Java SDK but you’re right, the C# one seems to gobble up those permission issue logs.

**Additional context**
As discussed in Slack #asherah