Add environment list retrieval and refactor BAP endpoint logic

[amitjoshi438]

This pull request includes several changes to the BAPService class and related utilities to enhance the functionality and improve code readability. The most important changes include renaming methods for clarity, adding new telemetry constants, and introducing a new utility function to fetch environment lists.

Key changes:

Enhancements to BAPService:

• Renamed the getBAPEndpoint method to getBAPCopilotCrossGeoFlagEndpoint for better clarity and updated its implementation to use the new getBAPEndpoint utility function.
• Updated the getCrossGeoCopilotDataMovementEnabledFlag method to call the renamed getBAPCopilotCrossGeoFlagEndpoint method.

New utility function:

• Added a new utility function getEnvList in Utils.ts to fetch the environment list for an organization, including necessary telemetry and error handling.

Telemetry constants:

• Introduced new telemetry constants VSCODE_EXTENSION_GET_ENV_LIST_SUCCESS and VSCODE_EXTENSION_GET_ENV_LIST_FAILED to track the success and failure of fetching environment lists.

Additional imports:

• Added necessary imports in Utils.ts to support the new utility function and telemetry constants.

Constants:

• Added BAP_ENVIRONMENT_LIST_URL constant to Constants.ts for the new environment list endpoint.

[priyanshu92]

Few small comments otherwise LGTM