[FEATURE REQUEST] Do not show workspace selection when only one workspace is active

[glektarssza]

Title kind of says it all.

By default, when newFile.relativeTo is set to project, the extension will ask you what project inside the workspace you want to create the file inside of even when there's only one project active.

Steps to Reproduce

1. Set newFile.relativeTo to project.
2. Open a single folder in a new workspace.
3. Activate the newFile.createNewFile command.
4. Observe the behaviour.

Expected Result

• The drop down proceeds directly to asking what the name of the file you want to create is.

Actual Result

• The drop down asks what project folder you want to use inside the workspace.