AWS SSO authentication fails with: Error: Unable to authenticate connection

## Problem

The extension looks amazing but I'm having trouble using it. I'm trying to get the extension to authenticate using my AWS SSO account via the existing profiles I have configured, however it is unable to do so.

## Steps to reproduce the issue

1. install the AWS Toolkit extension in my dev container
2. the `~/.aws` directory is mounted into the dev container, and the `aws` cli is installed:
```sh
$ which aws
/usr/bin/aws
$ aws --version
aws-cli/2.9.19 Python/3.11.2 Linux/6.4.16-linuxkit source/aarch64.debian.12 prompt/off
```
3. Authenticate with AWS via SSO ("Successfully logged into Start URL...")
4. Open the AWS extension panel and click "Select a connection..." under "Explorer"
5. Click one of my existing SSO profiles from `~/.aws/config` (e.g., `poweruser`):

> NOTE: none of these are expired or invalid

5. Get an error:

6. Confirm error in logs:

```sh
2023-12-01 12:17:32 [INFO]: log level: info
2023-12-01 12:17:32 [INFO]: endpoints: retrieving AWS endpoints data
2023-12-01 12:17:32 [INFO]: OS: Linux arm64 6.4.16-linuxkit
2023-12-01 12:17:32 [INFO]: Visual Studio Code extension host: 1.84.2
2023-12-01 12:17:32 [INFO]: AWS Toolkit: 2.1.0
2023-12-01 12:17:32 [INFO]: node: 18.15.0
2023-12-01 12:17:32 [INFO]: telemetry cache not found: '/home/humphd/.vscode-server/data/User/globalStorage/amazonwebservices.aws-toolkit-vscode/telemetryCache'
2023-12-01 12:17:32 [WARN]: AwsContext: no default region in credentials profile, falling back to us-east-1:
2023-12-01 12:17:33 [ERROR]: Profile default is not a valid Credential Profile: not supported by the Toolkit
2023-12-01 12:17:33 [WARN]: Shared Credentials Profile default is not valid. It will not be used by the toolkit.
2023-12-01 12:18:18 [ERROR]: _aws.auth.reauthenticate: Error: Unable to authenticate connection
-> CredentialsProviderError: Command failed: aws configure export-credentials

Unable to retrieve credentials: no credentials found
```

NOTE: If I run the same command myself, it works:

```sh
$ aws configure export-credentials
{
"Version": 1,
"AccessKeyId": "...redacted",
"SecretAccessKey": "...redacted",
"SessionToken": "...redacted",
"Expiration": "2023-12-01T13:18:07+00:00"
}
```

## Expected behavior

I would expect the extension to be able to use my current logged in SSO session without me having to do more work.

## System details (run the `AWS: About Toolkit` command)

OS: Linux arm64 6.4.16-linuxkit
Visual Studio Code extension host: 1.84.2
AWS Toolkit: 2.1.0
node: 18.15.0

Version: 1.84.2 (Universal)
Commit: 1a5daa3a0231a0fbba4f14db7ec463cf99d7768e
Date: 2023-11-09T10:52:33.687Z (3 wks ago)
Electron: 25.9.2
ElectronBuildId: 24603566
Chromium: 114.0.5735.289
Node.js: 18.15.0
V8: 11.4.183.29-electron.0
OS: Darwin arm64 22.6.0

Start by reproducing the failure in the AWS Toolkit extension inside the dev container, using the existing SSO profile and comparing it with the working `aws configure export-credentials` command. Trace the authentication flow and logs to determine why the extension cannot retrieve credentials; done means selecting the SSO profile authenticates successfully without extra user steps.

Written by the indexing model from the issue text.