Creating a new notebook does not pick up the preferred kernel.

[fcollonval]

Description

#10510 change the behavior of JupyterLab when creating a new notebook as it will select No kernel by default instead of preferred kernel: (animation show try JLab with latest stable VS master)

This breaks the UI-tests that assumes the preferred kernel is picked. But it was hidden due to #10528

Reproduce

1. Create a new notebook File -> New -> Notebook
2. Default selection is No kernel

Expected behavior

When a document has no kernel set, the preferred kernel should be selected by default.

Context

• Operating System and version:
• Browser and version:
• JupyterLab version:

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