Open An Org button presented when no Salesforce Project is open

**Describe the bug**
If I close a project in Code Builder, I am presented with a "Let's Get You Started" screen which has the option to Connect a Salesforce Org. But this will not work because the Salesforce tools don't open up unless I have a Salesforce project open, so this option should not actually be presented.

**To Reproduce**
Steps to reproduce the behavior:
1. Create a new Code Builder environment
2. Click "Hamburger" -> File -> Close Folder
3. "Let's Get You Started" screen appears with blue button to open a Salesforce Org

**Expected behavior**
No "Connect an Org" button should appear, it's not relevant in this context

**Screenshots**

**Desktop (please complete the following information):**
- OS: any
- Browser: any

**Smartphone or other device (please complete the following information):**
N/A

**Additional context**
Actually, it would be nice for this screen to not show up at all in this context, because, since the mechanism to hide this screen is via the `.vscode/settings.json` file in a Salesforce project, and this isn't a Salesforce project, it means this screen shows up every single time you close a project directory. They may not be what a user wants after they've used a Code Builder environment for a while.

Code Builder 環境を作成し、File > Close Folder からフォルダーを閉じて、「Let's Get You Started」画面を確認することで、問題を再現します。Salesforce プロジェクトで .vscode/settings.json メカニズムがこの画面を非表示にする仕組みを調査します。このコンテキストで、無関係な画面と「Connect an Org」ボタンが表示されなくなれば完了です。

索引モデルが issue の本文から書いたものです。