VS Code loading twice at workspace startup

Synced from eclipse/che issue

https://github.com/eclipse/che/issues/21400

Describe the bug

When starting a che-code based workspace the IDE gets loaded a first time and shows an error message (Error loading webview) and after a few seconds gets reloaded:

https://user-images.githubusercontent.com/606959/168334199-bb99188d-51eb-414c-b5f7-f6d5eae7bc4e.mov

Che version

next (development version)

Steps to reproduce

Click here (access to Che dogfooding instance is required).

Expected behavior

VS Code is loaded once.

Runtime

OpenShift

Screenshots

No response

Installation method

OperatorHub

Release Notes Text

An extension was used to open the project folder at VS Code startup. The result was VS Code beeing loaded twice in the user browser. This is not necessary anymore as we use the VS Code startup parameter --default-folder that has been (re-)introduced recently.