Deprecate VisualStudioCodeCredential

[scottaddie]

Ask: Deprecate VisualStudioCodeCredential (and VisualStudioCodeCredentialOptions). There's no path to success when using it. Apply [EditorBrowsable(EditorBrowsableState.Never)] to the class, and remove all mentions of the credential from the README and TSG.

Background: The VS Code Azure Account extension on which VisualStudioCodeCredential relies has been deprecated. Customers should use other dev-time credentials, such as AzureCliCredential, for their local development needs. Once the VS Code desktop app has authentication broker support (via MSAL Node.js) across Windows, macOS, and Linux, a broker-enabled instance of InteractiveBrowserCredential would be a great solution here. Unfortunately, that broker support only exists for Windows customers today, via WAM. Issue #30525 tracks the work to improve the devex for VS Code customers on Windows.

[github-actions]

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