[Feature Request]: Landing Page when no workflows open

### Is there an existing issue for this?

- [x] I have searched the existing issues and checked the recent builds/commits

### What would your feature do ?

This is a small thing, but it is very annoying to get a default "Unsaved Workflow" opened when all other workflows are closed. Then, we need to close that out and confirm we don't want to save the blank workflow to get rid of the tab. I imagine it would be a quick fix to have a default landing page that goes away when at least one workflow is opened.

### Proposed workflow

I imagine it would be a quick fix to have a default landing page that goes away when at least one workflow is opened.

### Additional information

_No response_

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-2473-Feature-Request-Landing-Page-when-no-workflows-open-1946d73d36508176babcfd297ef2622c) by [Unito](https://www.unito.io)