Plugin manager doesn't allow users to enable an extension

[divyansshhh]

Description

To disable extensions, the plugin manager seems to be writing the page_config to the sys_prefix location and not a location in the user directory. Whenever I try to disable a plugin it throws the following error in the UI -

Error when performing an action.
Reason given:
Error: PermissionError(13, 'Permission denied')

and the following error in the console -

ERROR 16:11:53 500 POST /lab/api/plugins?1701686512826 (choudhdi@10.240.172.120) 382.22ms referer=http://localhost:8888/lab/workspaces/auto-n

Reproduce

Try to disable any extension using the plugin manager.

Expected behavior

It shouldn't throw a permission denied error.

Context

jupyterlab==4.1.0a4

[krassowski]

Yes, sys_prefix as a non-configurable default was inherited from the extension manager. I think we should make it configurable, it should be rather straightforward (and the CLI commands already have a flag to configure it).