Don't block workspaces based on old model if Che is still able to run them

[slemeur]

Description

Right now Che is still available to run the workspaces which are based on the old model (GWT IDE and agents). But if a user has created one of those workspaces (from a stack or from a workspace definition), he'll be block with it, not being able to open it anymore.

The current behavior introduced by #13284 would be good, only when we would have remove completely the compatibility with the old model of workspaces.
(Should this be parameterized? or enabled only when a flag will be present?)

Until those workspaces can still run, we should not prevent the user from running them.

Reproduction Steps

• Create a workspace using a definition which will rely on the GTW IDE and Che 6 model
• Stop it
• See that you can't run it anymore

[ibuziuk]

@slemeur I think we can close this now since 7.0.0-RC-1.1 has been released

[che-bot]

Issues go stale after 180 days of inactivity. lifecycle/stale issues rot after an additional 7 days of inactivity and eventually close.

Mark the issue as fresh with /remove-lifecycle stale in a new comment.

If this issue is safe to close now please do so.

Moderators: Add lifecycle/frozen label to avoid stale mode.