VSCode extensions can use authentication providers to enable authentication actions from the Accounts menu, and to allow for federated authentication. The Sourcegraph Search extension needs neither of those - it can meet all of its authentication needs with the existing actions in is side panel.

On top of that, the authentication provider isn't implemented quite correctly, which leads to issues like #43608.

This PR removes the authentication provider.

It retains all of the expected behavior of the extension: the user can still authenticate against sourcegraph.com or private instances using an access token, and log out.

Test plan

First

Build and run locally.

git switch peterguy/vscode-remove-auth-provider
cd client/vscode
pnpm run build

Then

• Launch extension in VSCode: open the Run and Debug sidebar view in VS Code, then select Launch VS Code Extension from the dropdown menu.
• Note that the Accounts icon does not display a "1" badge and "Sign in with SOURCEGRAPH_AUTH" is not present in the menu.
• Click on Have an account? to open the login dialog.
• Enter an access token and the URL of the Sourcegraph instance to which you would like to connect.
• Click Authenticate account.
• Check the Accounts icon and menu - should not be anything there that's a result of Sourcegraph Search.
• In the Help and Feedback section, click your username to open the logout panel, then log out.
• Note again, the lack of modifications to the Accounts icon and menu from the Sourcegraph Search extension.

Changelog

• Remove interaction between the Sourcegraph Search extension and the Accounts menu.