AccessDeniedException Exception is occuring when connecting Amazon Q in VS Code

## Problem
AccessDeniedException when trying to connect Amazon Q in Visual Studio Code

## Steps to reproduce the issue

## Expected behavior
It should connect successfully
## System details (run `AWS: About` and/or `Amazon Q: About`)

**Note : Able to connect the AWS Toolkit extension**
- OS: Win 11
- Visual Studio Code version:1.101.2
- AWS Toolkit version:3.67.0
- Amazon Q version:1.79.0

[error] API response (oidc.us-east-1.amazonaws.com /token): {
name: 'AccessDeniedException',
'$fault': 'client',
'$metadata': {
httpStatusCode: 400,
requestId: '4dc8bf48-cfad-4d7a-8bcd-ffdb07dd4fd8',
extendedRequestId: undefined,
cfId: undefined
},
error: 'access_denied',
error_description: 'Access denied',
reason: null,
message: 'UnknownError'
}

Start by reproducing the connection attempt in Visual Studio Code with the reported Windows, AWS Toolkit, and Amazon Q versions, then inspect the OIDC /token response for the AccessDeniedException. Compare the Amazon Q authentication path with the working AWS Toolkit connection. Done means Amazon Q connects successfully without the reported access-denied response.

Written by the indexing model from the issue text.