Use the published gitpod theme in gitpod

[gtsiolis]

Bug description

Following up from #4281, when you install the newly published Gitpod Theme[1], users end up with duplicate theme entries.

Steps to reproduce

1. Open any workspace
2. Search and install the new Gitpod Theme
3. Set Gitpod Light or Gitpod Dark Theme
4. Open Color Theme Preferences
5. Notice the duplicate Gitpod Light and Gitpod Dark entries

Workspace affected

No response

Expected behavior

No response

Example repository

No response

Anything else?

No response

[jeanp413]

Yes, I will remove the ones that are built-in inside gp-code

[gtsiolis]

Thanks, @jeanp413! 🎲