[BUG] <IAM Auth using Sig4Auth is not working> with connector <Athena Neptune>

[kxrrrrrrr]

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. Neptune Engine 1.2.1.0
2. Set IAM Auth Enabled on Neptune
3. Set IAM Auth True on Application Repository Deployment
4. Failure will occur when attempting to connect to Neptune as viewable in Cloudwatch logs.

Expected behavior
A clear and concise description of what you expected to happen.
Connection into Neptune for Athena SQL Query to be translated into Gremlin and executed.

Screenshots / Exceptions / Errors
If applicable, add screenshots, exception stack traces, or error messages to help explain your problem. Stack traces for exceptions thrown by your Connector can be found in CloudWatch Logs under the 'aws/lambda/<Lambda_function_name>' log group.

Connector Details (please complete the following information):

• Version: [e.g. 2020.04.01 - if you are unsure, look at the tags on the Lambda function. One of the tag should contain the version if you deployed via Serverless Application Repo.]
• Name [e.g. redis, hbase, jdbc]
• Athena Query IDs [if applicable]

serverlessrepo:semanticVersion | 2023.42.1
serverlessrepo:applicationId | arn:aws:serverlessrepo:us-east-1:292517598671:applications/AthenaNeptuneConnector

Additional context
Add any other context about the problem here.