Attach-type debugging fails to display process picker if no file is open (isfs workspace)

[gjsjohnmurray]

Type: Bug

1. Have this workspace definition (alter URL to suit your local setup):

{
	"folders": [
		{
			"name": "irislatest:USER",
			"uri": "isfs://irislatest:user/"
		}
	],
	"launch": {
		"version": "0.2.0",
		"configurations": [

			{
				"type": "objectscript",
				"request": "launch",
				"name": "XDebug"
			},
			{
				"type": "objectscript",
				"request": "attach",
				"name": "Attach"
			}
		]
	}
}

2. Open the workspace.
3. Make sure no documents are open.
4. Go to Run and Debug view, choose Attach (workspace) on the dropdown and click the Start Debugging button.

🐛 instead of the expected process picker quickpick, a modal error messagebox appears:

Extension version: 2.12.7-beta.3
VS Code version: Code 1.91.1 (f1e16e1e6214d7c44d078b1f0607b2388f29d729, 2024-07-09T22:06:49.809Z)
OS version: Windows_NT x64 10.0.22631
Modes: