Bugfix if user cancels a kernel switching operation.
Bugfix if user cancels a kernel switching operation.

jupyter/jupyterlab,charnpreetsingh185/jupyterlab,charnpreetsingh185/jupyterlab,charnpreetsingh185/jupyterlab,jupyter/jupyterlab,charnpreetsingh185/jupyterlab,charnpreetsingh185/jupyterlab,jupyter/jupyterlab,jupyter/jupyterlab,eskirk/jupyterlab,eskirk/jupyterlab,jupyter/jupyterlab,eskirk/jupyterlab,eskirk/jupyterlab,eskirk/jupyterlab