feat(amazonq): update lsp clientname to support sagemaker unified studio case

[parameja1]

Problem

In order to set appropriate Origin Info on LSP side for SMUS CodeEditor, link, clientInfo needs to be distinct and with current logic that uses vscode.env.appName whose value will be same for all sagemaker codeeditor instances

• The original PR was reverted here due to failing unit tests
• Unit test failure was due to env variable SERVICE_NAME being modified directly from test code causing failure in other tests which identified the environment to be SMUS without clean isolation
• Fixed the test failure by using sinon stub instead of modifying env vars in node process

Solution

• To check if the environment is SageMaker and a Unified Studio instance and set corresponding clientInfo Name which is AmazonQ-For-SMUS-CE

Testing

• Built artefact locally using npm run compile && npm run package and tested on a SMUS CE space
• Ran npm run test -w packages/toolkit which succeeded
• LSP logs are attached to show the respective client Info details

[Trace - 9:55:46 PM] Sending request 'initialize - (0)'.
Params: {
    "processId": 6395,
    "clientInfo": {
        "name": "vscode",
        "version": "1.90.1"
    },
....
"initializationOptions": {
        "aws": {
            "clientInfo": {
                "name": "AmazonQ-For-SMUS-CE",
                "version": "1.90.1",
                "extension": {
                    "name": "AmazonQ-For-VSCode",
.....

• Tested the debug artefact in SMUS and SMAI spaces

As observed below, the sign out was only disabled for SMUS case initially with this change, a CR followed up which overrode the logic in isSageMaker and returned true for all cases irrespective of the appName passed

SMUS

SMAI

• Observing Q sendMessage failure in SMAI CE instance due to missing permissions, again unrelated to this change

---

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[amazon-inspector-ohio]

⏳ I'm reviewing this pull request for security vulnerabilities and code quality issues. I'll provide an update when I'm done

[amazon-inspector-ohio]

✅ I finished the code review, and didn't find any security or code quality issues.

[parameja1]

Close and open PR to retrigger CI runs

[amazon-inspector-ohio]

⏳ I'm reviewing this pull request for security vulnerabilities and code quality issues. I'll provide an update when I'm done

[github-actions]

• This pull request implements a feat or fix, so it must include a changelog entry (unless the fix is for an unreleased feature). Review the changelog guidelines.
  • Note: beta or "experiment" features that have active users should announce fixes in the changelog.
  • If this is not a feature or fix, use an appropriate type from the title guidelines. For example, telemetry-only changes should use the telemetry type.

[amazon-inspector-ohio]

✅ I finished the code review, and didn't find any security or code quality issues.