Suppress SM05137 in deserialization variable replacement settings (#3004)

## Why make this change?

Silences CodeQL flag.

## What is this change?

Adds the suppression language to the usage of `DefaultAzureCredential()`

## How was this tested?

Against usual test suite, no real code change, just a comment.

## Sample Request(s)

N/A

Author: aaronburtle

src/Config/DeserializationVariableReplacementSettings.cs

@@ -259,7 +259,7 @@ private static SecretClient CreateSecretClient(AzureKeyVaultOptions options)
                 clientOptions.Retry.NetworkTimeout = TimeSpan.FromSeconds(options.RetryPolicy.NetworkTimeoutSeconds ?? AKVRetryPolicyOptions.DEFAULT_NETWORK_TIMEOUT_SECONDS);
             }
 
-            return new SecretClient(new Uri(options.Endpoint), new DefaultAzureCredential(), clientOptions);
+            return new SecretClient(new Uri(options.Endpoint), new DefaultAzureCredential(), clientOptions); // CodeQL [SM05137] DefaultAzureCredential will use Managed Identity if available or fallback to default.
         }
 
         private string? GetAkvVariable(string name)