undo for code action `add extraPaths` doesn't work.

[heejaechang]

Try this https://github.com/microsoft/pylance-release/blob/main/testing/single/src/codeaction.py#L38

# place cursor on `outerModule` and confirm lightbulb shows up
# and trigger quick fix and confirm `Add "./outsideLib" to extraPaths` is listed
# execute the code action and confirm `extraPaths` is added to `settings.json`
import outerModule

and try Undo the code action.

Expected Behavior: It undo the setting changes Actual Behavior: No Undo

[luabud]

maybe we should open settings.json when this setting is modified? then if users want to undo it than can ctrl+z in the setting.json file directly