Update `type` for `Debugger Console` in layout customizations

[jtpio]

Follow-up to #7739

Update the following to Debugger Console after JupyterLab 4.5.0b1 (jupyterlab/jupyterlab#17939):

notebook/packages/application-extension/schema/shell.json

Line 12 in 79ad725

"Debugger console": { "area": "down" },