[JS] Add support for MSI in the CQA sample

[ceciliaavila]

[!IMPORTANT] This PR requires the feature introduced in #4879

Description

This PR adds support for User Managed Identity to the CQA sample. Providing a way to choose between using the EndpointKey or the MSI resource to authenticate to the Language service.

Proposed Changes

• Updated index.js to receive the new LanguageManagedIdentityClientId property. Additionally, the deprecated BotFrameworkAdapter was replaced by CloudAdapter.
• Updated RootDialog to support both EndpointKey and MSI auth type for CQA resource.
• Updated README.md to include the new MSI option and the required configuration.
• Updated .env file to include the new LanguageManagedIdentityClientId property.

Testing

The following image shows both types of authentication working.