can't access property "schema", registry.plugins[shortcuts.id] is undefined

[jtpio]

As noticed in #7859

Uncaught (in promise) TypeError: can't access property "schema", registry.plugins[shortcuts.id] is undefined
    node_modules notebook_core.19dcf7aa0c46b5f6.js:123269
    invokeSlot index.es6.js:555
    emit index.es6.js:513
    emit index.es6.js:112
    load settingregistry.js:236

This seems like race condition. Potentially related to this upstream PR: jupyterlab/jupyterlab#18163

[jtpio]

This does not look like a blocker for now, so we could look into it later

This seems like race condition. Potentially related to this upstream PR: jupyterlab/jupyterlab#18163

cc @brichet in case you may have more information