Workspaces does not persist after a reset.

[vidartf]

Reproduce

1. Open jupyterlab (binder here).
2. Create a new workspace (or keep the default one)
3. Open some files, modify the layout
4. Refresh the page to confirm that the workspace is persisted
5. Reset the workspace (/lab/workspaces/foo?reset)
6. The page is reloaded with the default layout.
7. Refresh the page.
8. The workspace is now back to how it was before the reset.
9. (optional) Do another reset, and then do some other changes. These will not be persisted either.